Self-assembled surfactant structures

ABSTRACT

Stabilized surfactant-based membranes and methods of manufacture thereof. Membranes comprising a stabilized surfactant mesostructure on a porous support may be used for various separations, including reverse osmosis and forward osmosis. The membranes are stabilized after evaporation of solvents; in some embodiments no removal of the surfactant is required. The surfactant solution may or may not comprise a hydrophilic compound such as an acid or base. The surface of the porous support is preferably modified prior to formation of the stabilized surfactant mesostructure. The membrane is sufficiently stable to be utilized in commercial separations devices such as spiral wound modules. Also a stabilized surfactant mesostructure coating for a porous material and filters made therefrom. The coating can simultaneously improve both the permeability and the filtration characteristics of the porous material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a continuation application of U.S. patentapplication Ser. No. 13/684,449, filed Nov. 23, 2012, which claimspriority to and the benefit of the filing of U.S. Provisional PatentApplication No. 61/562,956, filed Nov. 22, 2011, which is also acontinuation-in-part application of U.S. patent application Ser. No.13/113,930, filed May 23, 2011, which application claims priority to andthe benefit of the filing of U.S. Provisional Patent Application No.61/347,317, filed May 21, 2010, and U.S. Provisional Patent ApplicationNo. 61/415,761, filed Nov. 19, 2010, the disclosure of which are hereinincorporated by reference in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention (Technical Field)

Embodiments of the present invention employ biomimetic multiscale selfassembly and materials such as membranes made therefrom, fabricatedusing batch and automated manufacturing, in various configurations, toenable aqueous separations and concentration of solutes. Embodiments ofthe present invention also relate to methods of multiscale self assemblyand materials made therefrom where a surfactant mesostructure ispreferably simultaneously self assembled and integrated with one or morematerials by physical confinement between two or more discrete surfacesand/or by physical confinement on two or more sides.

Description of Related Art

Note that the following discussion may refer to a number of publicationsby author(s) and year of publication, and that due to recent publicationdates certain publications are not to be considered as prior artvis-à-vis the present invention. Discussion of such publications hereinis given for more complete background and is not to be construed as anadmission that such publications are prior art for patentabilitydetermination purposes.

Membranes are used to separate ions, molecules, and colloids. Forexample, ultrafiltration membranes may be used to separate water andmolecules from colloids which are 2 k Daltons or larger; ion exchangemembranes may be used to separate cations and anions; and thin filmcomposite membranes may be used to separate salt from water. Thesemembranes all use the same separation physics. The permeability of themembrane to a specific class or classes of ions, molecules, colloids,and/or particles is much less than another class or classes of ions,molecules, colloids, and/or particles. For example, ultrafiltrationmembranes have pores of a specific size which prevents the crossover ofmolecules and particles of a specific size. This technique is known assize exclusion. Reverse osmosis membranes use solubility differences toseparate molecules. In a typical thin film composite membrane, the wateris three orders of magnitude more soluble than sodium chloride. Theresult is a material that has a >100:1 preference of water molecules tosalt ions. In practical terms, the material filters water by rejecting99.7% of sodium chloride.

For most separation membranes the permeability of the membrane isdefined as the ratio of solvent flux through the membrane in a givenperiod of time to the area of membrane and the pressure applied to themembrane. Below is the equation governing the flux through a membrane

Flux=P*(ΔP−Δπ)

where ΔP is the pressure across the membrane, Air is the osmoticpressure across the membrane and P is the membrane permeability. Thepermeability of a membrane is a function of the membrane structureparameter. The structure parameter is

$S = \frac{\tau*t}{ɛ}$

where S is the structure parameter, τ is the tortuosity, t is thethickness, and ε is the porosity of the membrane. Tortuosity is definedas the ratio of the distance between two points through the material tothe minimum distance between the two points. Since the structureparameter is proportional to the permeability of the membrane, thetortuosity is proportional to the permeability.

Membranes for separations are used in many configurations. For reverseosmosis (RO) and forward osmosis (FO) applications, they are oftenconfigured in spiral wound architectures, in which the membrane iswrapped around a hollow core. Water flows from the core into a membraneenvelope and then back into the core. For pressure retarded osmosis(PRO), the membrane can also be in a spiral wound configuration. In PRO,water under pressure flows into the membrane envelope, and the osmoticgradient across the membrane pulls more water into the membraneenvelope. Membranes for RO, FO, and PRO can also be configured as hollowfibers. In hollow fibers, a hollow porous cylindrical membrane ismanufactured. Water flows tangential to the membrane surface and thepores in the fiber enable separation. Membranes can also be manufacturedas cartridges typically for the concentration of proteins, viruses,bacteria, sugar, and other biological materials. These membranes cancome in cassettes that enable easy concentration of solutes.

For the chloralkali process, batteries and fuel cells, the anode and thecathode are separated by an electrolyte. This electrolyte conductscations or anions and blocks electrons, liquid anolyte, and/orcatholyte. In some devices, the electrolyte is an ion exchange membrane.Typically, an ion exchange membrane will allow for the passage of eithercations or anions but not both. Ion exchange membranes can be configuredto allow for the passage of either both monovalent and divalent ions oronly monovalent ions. Transport across the electrolyte of undesiredsolutes is known as Membrane Crossover. Membrane Crossover createsoverpotential at the anode and/or the cathode, and reduces the currentefficiency of the cell. Membrane Crossover is a limiting factor in manydevices like direct methanol fuel cells, direct ethanol fuel cells,vanadium redox batteries, iron chrome batteries, flow batteries, etc.

In biology, water drives a class of surfactants called lipids to selfassemble in water creating a lipid bilayer which acts as a diffusionbarrier into the cell. The permeability of model cellular membranes towater and various low molecular weight solutes has been measured.Typical measurements of the selectivity of a lipid bilayer are performedin aqueous suspensions using osmosis (a.k.a. forward osmosis). Also, theresults of these experiments show that a lipid bilayer has greaterpermeability than commercial osmosis (a.k.a. forward osmosis) membranes.The model cellular membranes are phospholipids self assembled by waterinto structures called vesicles. A phospholipid has a hydrophilic headgroup and hydrophobic two fatty acid tails. A vesicle is a spherical,hollow, lipid bilayer between 30 nm and 20,000 nm in diameter. The lipidbilayer creates a physical barrier to the volume of water containedwithin the vesicle. A typical permeability experiment consists of twosteps. The first step is to change the osmotic strength of a solute inthe aqueous solution containing the vesicles. The second step is tomeasure the diffusion of the solute and/or solvent across the lipidbilayer into or out of the vesicles. This experiment is similar to theindustrial process of forward osmosis where water is extracted through amembrane using a highly concentrated brine solution.

The results of these experiments show that the hydrophobic core of thebilayer separates various low molecular weight compounds. One mechanismis the sub nanometer porosity created by the interstices between thelipids in the bilayer and the hydrophobic core of the bilayer enablepreferential selectively for water, protons, uncharged sub 100 molecularweight organics, and ions in that order. Also, fluctuations in themolecular structure of the bilayer enable faster than expected transportof water and protons. Furthermore, these experiments demonstratedcontrol over selectivity via the chemical structure of the lipids used.Specifically, the separation characteristics of the lipid bilayer aredependent on the length of the lipid's fatty acid tails.

SUMMARY OF THE INVENTION

An embodiment of the present invention comprises a membrane comprising astabilized surfactant mesostructure bonded to a surface of a poroussupport. The stabilized surfactant mesostructure is preferablystabilized with a material preserving an alignment of surfactantmolecules. The material is optionally porous and the stabilizedsurfactant mesostructure optionally comprises lamellae which alternatewith lamellae comprising the porous material. Alternatively, thematerial is optionally non-porous and the stabilized surfactantmesostructure optionally comprises hexagonally packed columns comprisingcircularly arranged surfactant molecules, each of the columnssubstantially surrounded by the non-porous material. The membranepreferably further comprises a material disposed between the stabilizedsurfactant mesostructure and the surface for preserving a hydrogenbonding network between surfactant in the stabilized surfactantmesostructure and the surface. The material preferably comprises amaterial selected from the group consisting of silanes, organics,inorganics, metals, metal oxides, an alkyl silane, calcium, and silica.The surface preferably has been oxidized, melted and resolidified priorto bonding of the stabilized surfactant mesostructure on the surface; insuch case an average pore size at the resolidified surface is preferablysmaller than average pore size in a bulk of the porous support. A poresize of the porous support is preferably sufficiently small to prevent aprecursor solution to the stabilized surfactant mesostructure fromcompletely permeating the support prior to formation of stabilizedsurfactant mesostructure. The membrane optionally further comprises anadditional porous structure disposed on a side of the porous supportopposite from the surface for mechanically or chemically stabilizing theporous support. The stabilized surfactant mesostructure optionallycomprises a transporter. The membrane optionally comprises a secondporous support, wherein the stabilized surfactant mesostructure issandwiched between the porous support and the second porous support. Themembrane preferably comprises a tortuosity of less than approximately1.09. The stabilized surfactant mesostructure preferably comprises apore size between approximately 0.3 Angstroms and approximately 4 nm.The membrane preferably comprises a porosity greater than approximately1%. The porous support preferably comprises plastic and/or cellulose.The porous support preferably mechanically stabilizes the stabilizedsurfactant mesostructure. The membrane optionally further comprises asecond stabilized surfactant mesostructure bonded to a side of theporous support opposite from the surface. The membrane is optionallystacked with other same membranes, thereby forming a multilayermembrane. The surface of the stabilized surfactant mesostructure isoptionally modified. The membrane optionally comprises an ion-exchangemembrane and/or a gas diffusion layer, the membrane comprising amembrane electrode assembly or an electrolyte.

Another embodiment of the invention is a method for producing amembrane, the method comprising modifying a surface of a porous support;wetting the modified surface with a first solvent; disposing a solutionon the wetted surface, the solution comprising at least one surfactantand at least one second solvent, wherein the at least one surfactant isin the dispersed phase in the solution; confining the solution betweentwo or more confining surfaces; and stabilizing the one or moresurfactants to form a stabilized surfactant mesostructure on the surfaceof the porous support. The first solvent and/or the second solventpreferably comprises water. The solution optionally further comprises aprecursor solute and/or a transporter. Disposing the solution andconfining the solution are optionally performed substantiallysimultaneously. Confining the solution preferably comprises confiningthe solution between a surface of the porous support and at least onesecond surface. The at least one second surface is preferably selectedfrom the group consisting of a groove sidewall, a roller, and a bladeedge. Modifying the surface preferably comprises an action selected fromthe group consisting of surface functionalization, surface grafting,covalent surface modification, surface adsorption, surface oxidation,surface ablation, surface rinsing, depositing a material on the surface,the material selected from the group consisting of silanes, organics,inorganics, metals, metal oxides, an alkyl silane, calcium, and silica,preserving a hydrogen bonding network between surfactant in thestabilized surfactant mesostructure and the surface, and oxidizing,melting and resolidifying the surface, and combinations thereof. Themethod is preferably performed as part of a mass production coatingprocess. The method preferably further comprising controlling athickness of the stabilized surfactant mesostructure. The solutionoptionally does not comprise an acid, a base or a hydrophilic compound.The at least one surfactant is preferably not removed from the solutionafter the solution is disposed on the surface. The method is optionallyperformed on both sides of the porous support. The method of optionallyfurther comprises modifying a surface of the stabilized surfactantmesostructure, preferably utilizing surface functionalization, changingthe hydrophobicity of the surface of the stabilized surfactantmesostructure, and/or methylating the surface of the stabilizedsurfactant mesostructure. The method may be repeated to form amultilayer membrane. The porous support preferably comprises plasticand/or cellulose. The method optionally further comprises disposing asecond porous support on a surface of the stabilized surfactantmesostructure, thereby sandwiching the stabilized surfactantmesostructure between the porous support and the second porous support.

Another embodiment of the present invention is a forward osmosismembrane comprising a permeability of greater than approximately 15LM⁻²H⁻¹ for a draw solution concentration of 10 wt % NaCl at 20° C. Thepermeability is preferably greater than approximately 20 LM⁻²H⁻¹ for adraw solution concentration of 10 wt % NaCl at 20° C., and even morepreferably greater than approximately 60 LM⁻²H⁻¹ for a draw solutionconcentration of 10 wt % NaCl at 20° C. The forward osmosis membranepreferably comprises a rejection of NaCl greater than approximately 96%.The forward osmosis membrane preferably comprises one or moresurfactants.

Another embodiment of the present invention is a device for performingseparations, the device comprising an active layer which comprises oneor more surfactants. The active layer preferably comprises one or moretransporters. The device is preferably selected from the groupconsisting of a forward osmosis membrane or module, a reverse osmosismembrane or module, a pressure retarded osmosis membrane or module, ahollow fiber membrane, a spiral wound membrane or module, a cartridge, aTangential Flow Filter (TFF) cartridge, a plate and frame module, atubular membrane, and a bag. The device preferably comprises a poroussupport coated on both sides with the one or more surfactants. The oneor more surfactants preferably form a membrane mechanically stabilizedon one or more porous supports.

Another embodiment of the present invention is a hydrophilic coating fora porous material, the coating comprising an inorganic material derivedfrom a sol-gel precursor. The inorganic material comprises silica and/oralumina. The coating optionally comprises a stabilized surfactantmesostructure, the stabilized surfactant mesostructure comprising one ormore single chain surfactants. The surfactants optionally have a chargeselected from the group consisting of anionic, cationic, zwitterionic,and non-ionic, and combinations thereof. The stabilized surfactantmesostructure preferably comprises between approximately 1 andapproximately 20 wt % surfactants.

Another embodiment of the present invention is a filter comprising aporous material coated with the coating of claim 1. The porous materialis preferably selected from the group consisting of plastic, ceramic andmetal. The average pore size of the filter is preferably less than theaverage pore size of the porous material. The filter preferably has anaverage pore size greater than 0.001 microns, and more preferablybetween 0.002 microns and approximately 0.4 microns. The molecularweight cutoff of the filter is preferably less than a molecular weightcutoff of the porous material. The porous material preferably has amolecular weight cutoff between approximately 100 daltons andapproximately 500,000 daltons. The porous material preferably comprisesa filter selected from the group consisting of a microfiltrationmembrane, an ultrafiltration membrane, a nanofiltration membrane, abackflushable membrane, and a reverse osmosis membrane. The porousmaterial preferably comprises polyethersulfone (PES), polysulfone (PS),polyvinyldiflouride (PVDF), poly acrylic nitrile (PAN), or a blendthereof. The water permeability and the emulsion permeability of thefilter is preferably at least 10% greater than the water permeability ofthe porous material. Rejection of a substance by the filter ispreferably at least 10% greater than rejection of the substance by theporous material, the substance preferably selected from the groupconsisting of polyethylene glycol, a salt, an organic material, totaldissolved solids, and an emulsion, preferably in conjunction with theenhanced permeability. Turbidity of a filtrate filtered by the filter ispreferably at least 10% lower than turbidity of a filtrate filtered bythe porous material, preferably in conjunction with the enhancedpermeability. A diameter of a drop of water wetting the filter ispreferably at least approximately 10% greater, more preferably at leastapproximately 30% greater, and even more preferably at leastapproximately 50% greater than a diameter of a drop of water of the samevolume wetting the porous material. The filter optionally comprises apartially or completely electrostatic separation mechanism. The filtermay optionally be formed into an element, such as a spiral woundelement, used in a water treatment system. The system optionallycomprises a two stage process comprising amicrofiltration/ultrafiltration stage and a reverse osmosis stage. Thefilter of claim 6 is preferably useful for filtering a fluid selectedfrom the group consisting of wastewater, wastewater comprisingsurfactants, wastewater comprising an emulsion, bilge water, grey water,laundry water, and emulsions.

An embodiment of the filter is used as a forward osmosis membrane, whichoptionally has a molecular weight cutoff when used in a reverse osmosisconfiguration which is at least an order of magnitude different than amolecular weight cutoff when used in a forward osmosis configuration.The membrane's forward osmosis flux is preferably greater thanapproximately 60 LMH and urea rejection is greater than approximately60%. The membrane preferably utilizes a forward osmosis separationmethod that is not the solution diffusion mechanism.

Objects, advantages and novel features, and further scope ofapplicability of the present invention will be set forth in part in thedetailed description to follow, taken in conjunction with theaccompanying drawings, and in part will become apparent to those skilledin the art upon examination of the following, or may be learned bypractice of the invention. The objects and advantages of the inventionmay be realized and attained by means of the instrumentalities andcombinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated into and form a partof the specification, illustrate several embodiments of the presentinvention and, together with the description, serve to explain theprinciples of the invention. The drawings are only for the purpose ofillustrating an embodiment or embodiments of the invention and are notto be construed as limiting the invention. In the drawings:

FIGS. 1A and 1B illustrate how the interstices between surfactantmolecules in a lamellar phase can be used for separation.

FIGS. 2A, 2B, 2C and 2D illustrate how the interstices betweensurfactant molecules in a hexagonal phase can be used for separation.

FIGS. 3A, 3B, 3C and 3D illustrate how the interstices betweensurfactant molecules in an inverse hexagonal phase can be used forseparation.

FIG. 4 illustrates a process to localize surfactant mesophase thin filmself assembly to the surface of a porous material. The result is afreestanding surfactant mesophases material adhered to a porousmaterial.

FIG. 5 shows an embodiment of a stabilized surfactant mesostructure thinfilm where the assembly was localized to the surface of a porousmaterial.

FIGS. 6A and 6B illustrate the physical confinement method used tocreate the displayed free standing surfactant templated membrane.

FIG. 7 is a schematic of a biomimetic surfactant nanostructure assembledvia physical confinement.

FIGS. 8A, 8B and 8C illustrate various configurations of two dimensionalmultiscale self assembly in accordance with embodiments of the presentinvention.

FIGS. 9A and 9B illustrate the effect of membrane material surfacechemistry preparation on the flux and rejection levels of the resultantmaterial.

FIG. 10 shows the effect of concentration polarization of methanol onthe flux through a biomimetic surfactant nanostructure

FIGS. 11A and 11B show membrane thickness control via self assemblysolution solute concentration and its effect on permeability.

FIG. 12 shows membrane thickness control via physical confinement andits effect on permeability.

FIG. 13 is a schematic of an embodiment of an automated roll to rollstyle process for manufacturing membranes.

FIG. 14 shows the effect of annealing on membrane permeability.

FIG. 15 shows the difference between symmetric and asymmetric membranes.

FIG. 16 is a plot of the back diffusion of salt comparing a symmetricand an asymmetric free standing biomimetic surfactant nanostructure.

FIG. 17 shows the effect of surface functionalization chemistry onmembrane hydrophobicity.

FIG. 18 shows a design for an embodiment of a cartridge using flatmembranes for separation and concentration.

FIG. 19 shows a design for an embodiment of a spiral cartridge used forconcentration of solutes.

FIG. 20 shows a design for an embodiment of a spiral cartridge used forpurification of water.

FIGS. 21A and 21B illustrate the effect of pressure on the rejectionlevels of an embodiment of a membrane in accordance with the presentinvention.

FIG. 22A and FIG. 22B illustrate the effect of a mechanical backing onthe long term stability of an embodiment of a membrane.

FIG. 23 demonstrates the use of an embodiment of the membrane toconcentrate methanol.

FIGS. 24A and 24B measure the effect of alcohol on various supports.

FIGS. 25A and 25B demonstrate the effect of an underlying support on theseparation of ethanol.

FIG. 26 demonstrates the use of an embodiment of the membrane toconcentrate ethanol.

FIG. 27 demonstrates NaCl rejection by an embodiment of the membrane.

FIG. 28 demonstrates MgSO₄ rejection by an embodiment of the membrane.

FIG. 29 shows a cross section of an embodiment of a multilayer membrane.

FIGS. 30A and 30B show ethanol rejection of an embodiment of a 3 BSNSlayer membrane.

FIG. 31 shows butanol rejection of an embodiment of a 4 BSNS layermembrane.

FIGS. 32A, 32B, 32C and 32D show the through plane conductivity,methanol permeability and stability of a biomimetic surfactantnanostructure.

FIG. 33 is a schematic of a multiscale self assembled membrane used inan electrochemical cell.

FIGS. 34A and 34B depict embodiments of a lamellar structure comprisingsingle chained surfactants in a z-dimensional nanostructure.

FIGS. 35A and 35B depict embodiments of a lamellar structure comprisingdumbbell shaped molecules in a z-dimensional nanostructure.

FIG. 36 depicts an embodiment of a z-dimensional lamellar structurecomprising a mixture of one or more single chain surfactants and/ordumbbell molecules.

FIG. 37 depicts an embodiment of a lamellar structure with three layersof distinct self assembled material.

FIG. 38 shows increased wetting of microfiltration membranes by coatingwith a mesostructured sol gel film.

FIG. 39 shows increased wetting of ultrafiltration membranes by coatingwith a mesostructured sol gel film.

FIG. 40 demonstrates the improved filtration properties of a porousmaterial coated with a mesostructured sol gel film for solutionscontaining surfactants and no oil.

FIG. 41 demonstrates the improved filtration properties of a porousmaterial coated with a mesostructured sol gel film for solutionscontaining surfactants and oil.

FIG. 42 demonstrates improved model bilge water filtration properties ofa porous material when coated with a mesostructured sol gel film.

FIG. 43 compares performances of surfactants comprising themesostructure with different charges.

FIGS. 44A and 44B show the effectiveness of an embodiment of the presentinvention when filtering turbid laundry waste water.

FIGS. 45A and 45B show schematics of a surfactant templated thin filmassembled on a porous surface.

FIG. 46 shows urea rejection under forward osmosis of an embodiment ofthe present invention.

FIG. 47 is a schematic showing a simple flow diagram of a two stagemicrofiltration/ultrafiltration, reverse osmosis water treatment system.

DETAILED DESCRIPTION OF THE INVENTION Definitions

As used throughout the specification and claims, the following terms aredefined as follows:

“Amphiphile” means a molecule with both solvent preferring and solventexcluding domains.

“Hydrophilic” means water preferring. Hydrophilic compounds and surfaceshave high surface tension.

“Hydrophobic” means water repelling. Hydrophobic compounds and surfaceshave low surface tension.

“Surfactant” means a class of amphiphiles having at least one domainwhich is hydrophilic and at least one domain which is hydrophobic.Systems that are engineered to work with surfactants can most likelywork with all amphiphiles.

“Phospholipid” means the majority constituent of the cellular membrane.These molecules self assemble into vesicles in water and exist in thedispersed phase in a low surface tension solvent.

“Lamellar” means comprising multiple layers or bilayers.

“Mesophase” means a surfactant liquid crystal structure formed by theinteractions between one or more solvents and one or more surfactants.

“Micelle Phase” means a spherical phase of surfactants where thehydrophobic domains of the surfactants are hidden from the bulk solutioninside the micelle.

“Critical Micelle Concentration” means the concentration above whichsurfactants order into micelles.

“Hexagonal Phase” means a two dimensional hexagonal arrangement ofcylinders of surfactants where the hydrophobic domains of thesurfactants are inside the cylinders.

“Inverse” means a surfactant structure where the hydrophilic domains areon the inside of the structure. For example, a surfactant in oil formsan inverse micelle where the hydrophilic heads are hidden from the bulksolution inside the micelle.

“Stabilized Surfactant Mesostructure” means a mesophase that maintainsits structure after the removal of the solvents.

“Self Assembled Surfactant Thin Film” means a film, typically less thanor equal to ten microns in thickness, wherein one component of the filmis a mesophase.

“Biomimetic Membrane” means a single phospholipid bilayer comprising atransporter.

“Biomimetic Surfactant Nanostructure (“BSNS”)” means a lamellarstabilized surfactant mesostructure, which may or may not comprise atransporter, assembled on a porous support.

“Transporter” means a molecule, complex of molecules, a structure, aprotein, a zeolite, an ion channel, a membrane protein, a carbonnanotube, cyclodextrin, or any other structure that modulates thetransport rates of a specific class of ions, molecules, complex ofmolecules, biological structures, and/or colloidal particles.

“Free Standing” means surfactant template thin film where both sides ofthe film are addressable to solution and the film is not necessarilyconfined by physical barriers.

“Supported” means a material is assembled on a second material such thatthe second materials imbues mechanical stability to the first materialwithout eliminating all of its functions.

“Hollow Fiber Membrane” means a hollow porous cylindrical structure.This material is similar to a straw except it is porous. This materialis typically used for aqueous separations.

“Membrane/Semi Permeable Membrane” means a material used to separatespecific classes of ions, molecules, proteins, enzymes, viruses, cells,colloids, and/or particles from other classes.

“Mechanical Backing” means a solid or porous support used to increasethe mechanical stability of a second material.

“Concentration Polarization” means during filtration, localconcentration of a compound at the surface of the membrane differs fromthe bulk concentration of the compound.

“Reverse Osmosis” means a process that uses pressure to separate saltand water.

“Forward Osmosis” means a process that uses an osmotic gradient tocreate water flux.

“Pressure Retarded Osmosis” means a process that uses an osmoticgradient and pressure to capture energy from forward osmosis.

“Membrane Crossover” means transport across an electrolyte of anundesirable molecular or ionic species.

“Overpotential” means a reduction in a half electrochemical cell'spotential from the theoretically expected value. Membrane Crossover canbe a cause of overpotential of a half electrochemical cell.

“Single chain surfactant” means a surfactant having only one hydrophilicdomain and only one hydrophobic domain, wherein the hydrophobic domaincomprises only one alkyl chain.

“Emulsion” means a solution comprising water, at least one amphiphile,and oil.

“Filter” means a material used to remove solutes from solutions,including but not limited to a membrane, a microfiltration filter ormembrane, an ultrafiltration filter or membrane, reverse osmosis filteror membrane, forward osmosis filter or membrane, hollow fiber membrane,and semi-permeable membrane.

Definitions of Material Preparation Methods

The following methods were used to prepare surfaces for the assembly ofsurfactant templated sol-gel thin films. Each material was rinsed inwater, ethanol, then dried before another further preparation. Allmaterials were stored in water before use. UV light source was an ozoneproducing pen lamp from UVP.

“Rinse Only”—Materials were not further treated after rinsing.

“UV Clean”—Materials were exposed to ozone producing UV light from a penlamp for greater than 1 minute. After treatment, Materials were storedin water.

“UV Clean Net”—Materials were exposed to ozone producing UV light from apen lamp for greater than 1 minute. After treatment, materials werestored in water. Before self assembly solution deposition, a microporousmesh was placed between the solid surface and the membrane in thephysical confinement cell.

“H2O2 Boil”—Materials were rinsed in hot (>20° C.) hydrogen peroxide forone hour.

“H2O2 Boil TEOS”—Materials were rinsed in hot (>20° C.) hydrogenperoxide for one hour. Then materials were soaked in stock silicasolution, allowed to air dry for at least three hours, and finally curedat >80° C. for more than three hours.

“UV TEOS”—Materials were exposed to ozone producing UV light from a penlamp for greater than 1 minute. Then materials were soaked in stocksilica solution, allowed to air dry for at least three hours, andfinally cured at >80° C. for more than three hours.

Surfactant Mesostructures

Surfactant mesostructures may be used for separations in accordance withembodiments of the present invention. There are at least threeindependent mechanisms for separations using surfactant mesostructures.The first comprises using the interstices between surfactants inmesostructures. The interstices have several advantages for separations,including but not limited to low tortuosity, tunable pore size, tunablesurface charge, and either apolar or polar pores. Furthermore, thethickness of surfactants in mesostructures is easy to control. Thesecond mechanism is molecular transport through defects, enablingselectivity in the thin film. These defects can be on the molecularlevel (e.g. a missing molecule or a poorly fitting molecule) and/or onthe macroscopic level (e.g. from wetting instabilities duringdeposition). The third mechanism is that the surfactant mesostructurecan form pores itself via the entrapment of solvent during formation.After formation, solvent can be removed to enable transport or canremain, similar to a water wire in biology, to enable transport.Although this embodiment of the present invention is inspired bybiological (e.g. cellular) membranes, it preferably does not comprise abiomimetic membrane, because the invention requires material nanoscienceto stabilize the self assembled surfactant thin films and integrate themwith devices. This embodiment of the present invention is alsopreferably not a surfactant templated sol-gel material because itpreferably uses the physical properties of the surfactant mesostructureto separate compounds rather than using the surfactant to create adesirable sol-gel structure. In other words, embodiments of the presentinvention preferably utilize the surfactant, and not an inorganicsol-gel structure such as silica or titanium dioxide, to form thestructure of the stabilized surfactant mesostructure. Embodiments of thepresent invention comprise stabilized surfactant mesostructures,including but not limited to a lipid bilayer, for separations, includingbut not limited to osmosis.

The desirable permeability and separation capability of a stabilizedsurfactant mesostructure is related to the simplest class of embodimentsof this invention: a one dimensional crystal of surfactants assembled inthe lamellar phase. One specific embodiment within this class isz-dimensional lamellae of lipid bilayers. The lipid bilayers use theenergy penalty of molecules in the oil phase composed of the lipid tailsto create a solubility barrier, limiting transport across the membrane.This mechanism can be modeled by the solubility diffusion model. Waterand protons travel across the membrane through spontaneous pores whichform in the membrane, as shown in FIGS. 1A and 1B. FIG. 1A is a sidecross-sectional view of the lamellar bilayer surfactant structure. Thehydrophilic domains of surfactants are represented by the stippled graycircles. The hydrophobic domains of the surfactants are represented bythe two stippled black lines. The arrows show the path of moleculesbetween the surfactants. FIG. 1B is a top view of the lamellar bilayersurfactant structure. The stippled grey circles represent thesurfactants. The black dots represent interstices between thesurfactants which enable transport through the structure.

This embodiment differs from classic biomimetic membranes where an ionchannel and/or another transporter is included within the surfactant. Inthose systems, transport across the membrane is a function of thechannel or transporter. This embodiment of the invention is a membranewhich does not comprise a transporter or ion channel. Alternatively,other embodiments of the present invention may comprise one or moretransporters, but are preferably multilayer and therefore not biomimeticmembranes.

X-ray diffraction measurements have established that the diameter of alipid is 7.189 Å. Assuming that lipids in the plane are locally closepacked and can be represented as circles, the diameter of a circleinscribed between the lipids is 1.112 Å. For reference, a bond length istypically between about 1.0 Å and about 2.5 Å. This enables thesurfactant to perform size exclusion separations at the atomic level. Inthis class of embodiments, X-ray experiments have shown that thedistance between two sides of a single bilayer is approximately 42.00 Å.The maximum/minimum path length of a molecule through the single bilayeris approximately 45.59 Å/42.00 Å. The maximum path length occurs whenthe lipids of one layer sit on the interstices of the other lipid layer.Therefore, the tortuosity of a single bilayer is between about 1.09 and1.00. In the minimum case for the self assembled mesophase, thetortuosity of the material is 1.00, by definition the minimum tortuositypossible. The tortuosity of the present membranes is preferablyapproximately close to the tortuosity of a single lipid bilayer. Thisenables the present membranes to have a structure parameter ofpreferably less than 0.5 mm, and more preferably less than about 0.1 mm.Material science techniques preferably control the number ofz-dimensional lamella to be from one to thousands. The effect on watertransport of the sol-gel layer is negligible, because the porosity ishigh, the thickness is several molecules, and the tortuosity is nearone.

In the lamellar class of embodiments, the porosity of the lamellae canbe controlled by using different sizes and shapes of surfactants andmixtures of surfactants. For example, the diameter of the interstitialpores between the surfactants is 15.5% of the diameter of thesurfactants when the surfactants are modeled as a plane of circles. Forexample, a single chain surfactant has a smaller in-plane area than alipid. The result is a membrane comprising smaller pores. In oneembodiment, lamellae of lipid bilayers were assembled on a microporoussupport using a variety of methods included in this invention. Asexpected, when compared to current forward osmosis membranes, thestabilized surfactant mesostructure has higher permeability to water. Inthis embodiment, the surfactant is in the lamellar phase. Thisembodiment will be described in detail later. The result of thisexperiment is summarized in TABLE 1. As can be seen, the permeability ofthe stabilized surfactant mesostructure of the present embodiment isapproximately five times greater than a typical commercial FO membrane.Thus the present invention can have a permeability of greater than 15LM⁻²H⁻¹, more preferably greater than 20 LM⁻²H⁻¹, and even morepreferably greater than 60 LM⁻²H⁻¹ for a draw solution concentration of10 wt % NaCl at 20° C. Further, for these membranes, the rejection ofNaCl was greater than approximately 96%.

TABLE 1 Draw Solution Membrane Permeability Concentration Commercial FO  15 LM⁻²H⁻¹ 10 wt % NaCl Membrane Stabilized Surfactant 75.5 LM⁻²H⁻¹ 10wt % NaCl Mesostructure

Surfactants can self assemble into a lamellar phase, hexagonal phase,and/or cubic phase. Specifically applicable surfactants includesurfactants with ammonium salt, caroboxylic acid, alcohol, amine,sulfate, phosphate, phosphonate and sulfonate moieties. Examples ofmolecules that can form desirable structures as a single component or inmixtures in a self assembly solution include dodecanol, dodecane amine,lauric acid, and/or myristyl trimethyl ammonium bromide. Specificallyapplicable surfactants include surfactants that have longer, shorter,branched or cyclic alkane chains to those mentioned in the previoussentence may also be desirable as a single component or as a componentin a mixture in a self assembly solution. This is illustrated in FIGS.34A and 34B, which illustrates embodiments of a lamellar structure withsingle chained surfactants in a z-dimensional nanostructure. In thisembodiment, each layer is a z-dimensional nanostructure. One or more ofthe layers may optionally not be lamellar in the multilayeredstructures. FIG. 34A depicts a z-dimensional lamellar structurecontaining a single chain surfactant. FIG. 34B depicts a z-dimensionallamellar structure containing a mixture of one or more single chainsurfactants. Although in this figure each layer is represented by threelamellae, a layer may comprise any number of lamellae.

In the previous examples, surfactants may self assemble to form phasesincluding a lamellar phase which consists of periodic bilayer surfactantstructures. Surfactants and bilayers are not necessary for separations.A bilayer can be simulated by a single layer by replacing the twomolecules in a bilayer with one molecule. That single moleculepreferably comprises both moieties which were present at the surface ofthe bilayer and both alkane moieties of the two molecules which werereplaced. For example, a bilayer composed of hexanol can be replaced by1,12 dihexanol. The two hydroxyl groups on the opposite ends of thealkane create a ‘dumbbell’ shaped molecule. Similar examples exist indi-ammonium salts, di-caroboxylic acids, di-alcohols, di-amines,di-sulfates, di-phosphates, di-phosphonates and di-sulfonates. Thealkane moieties can be substituted in a one-one carbon basis orcompletely changed. For example, the two molecular layers of a dodecanolbilayer can be substituted with one 1,12 dodecandiol, as shown in FIGS.35A and 35B. In general, FIGS. 35A and 35B depicts embodiments of alamellar structure comprising dumbbell shaped molecules in az-dimensional nanostructure. In this example, each layer is az-dimensional nanostructure. One or more of the layers may optionallynot be lamellar in the multilayered structures. FIG. 35A depicts az-dimensional lamellar structure containing a single dumbbell (two-end)shaped molecule. FIG. 35B depicts a z-dimensional lamellar structurecontaining a mixture of one or more dumbbell shaped molecules. Althoughin this figure each layer is represented by three lamellae, a layer maycomprise any number of lamellae.

A lamellar structure may comprise both surfactants and dumbbell shapedmolecules in a z-dimensional nanostructure as illustrated in FIG. 36. Inthis embodiment, each layer is a z-dimensional nanostructure. One ormore of the layers may optionally not be lamellar in the multilayeredstructures. The pictured z-dimensional lamellar structure comprises amixture of one or more single chain surfactants and/or dumbbellmolecules. Although in this figure each layer is represented by threelamellae, a layer may comprise any number of lamellae.

Thus a single surfactant, or one or more of a mixture of surfactants,used to make membranes in some embodiments of the present invention maybe cationic, anionic, zwitterionic and/or nonionic. A single moleculecomprising two ionic groups connected by an alkyl or alkane may be used.A single molecule, or one or more of a mixture of molecules, comprisinga diol, dicarboxylic acid, diamine, and/or diammonium salt may be used.A mixture of molecules which are any of the following may be used:cationic surfactants, anionic surfactants, zwitterionic surfactants,nonionic surfactants, diols, dicarboxylic acid, diamines, and/ordiammonium salts.

In cells, lipid membranes are used to enable selective transport intoand out of the cell without the use of external pressure. Below is asummary of the experimentally measured permeability of water (TABLE 2),ions (TABLE 2) and small molecules (TABLE 3) across a lipid bilayer.Without ion channels, water permeates lipid bilayers faster than otherions and molecules. With gramicidin, an ion channel, water andmonovalent ion permeability increases, resulting in enhanced separationefficiency of water from molecules and decreased selectivity of waterfrom monovalent ions. The permeability of a membrane containinggramicidin was calculated from the flux (ml/min) of gramicidin at 10%density in a lipid bilayer. For the calculation, the area per lipid (thesolvent), one molecule per 0.596 nm², was used instead of the area pergramicidin (the solute). The area of gramicidin was 10% calculated as10% of the molecules in the bilayer. The permeability of potassiumthrough the gramicidin containing membrane was calculated by assuming an8:1 water to potassium ion stoichiometry. Sodium transport wascalculated from potassium transport using the well known sodium topotassium conductivity ratio of 0.338.

TABLE 2 Water Potassium Sodium w/10 ml % w/10 ml % w/10 ml % Watergramicidin Potassium gramicidin gramicidin Chlorine Calcium Permeability0.025 0.27 1.51 × 10⁻¹⁰ 3.38 × 10⁻² 1.00 × 10⁻² 2.80 × 10⁻⁸ 8.00 × 10⁻¹⁵(cm/sec) Permeability 900 9.72 × 10³ 5.44 × 10⁻⁶  1.22 × 10³  3.60 ×10⁻² 1.01 × 10⁻³ 2.88 × 10⁻¹⁰ (L M⁻²H⁻¹)

TABLE 3 Methanol Ethanol Butanol Urea Glycerol Permeability 1.20 × 3.80× 1.20 × 3.40 × 6.20 × (cm/sec) 10⁻⁵ 10⁻⁵ 10⁻³ 10⁻⁶ 10⁻⁶ Permeability0.432 1.37 43.2 0.122 0.223 (L M⁻²H⁻¹)

Different transporters may optionally be used to change selectivity.Transporters of interest include, but are not limited to, aquaporin forfast water permeation, chemically modified natural channels, some ofwhich increase water permeability (e.g. desformylgramicidin), and/orchemically modified natural channels, some of which affect selectivityfor specific ions and/or molecules (e.g. modified alpha hemolysin).Aquaporin and desformylgramicidin have greater than 100× increased waterflux compared to gramicidin A. The difference in permeability of waterversus other solutes makes lipid bilayers ideal for separation,particularly for low pressure applications.

In another class of embodiments of the present invention, stabilizedsurfactant mesostructures are in either the hexagonal phase or theinverse hexagonal phase. In the hexagonal phase, the surfactants selfassemble into a hexagonal lattice of cylinders with surfactant'shydrophobic domains hidden from the hydrophilic interstices' between thecylinders. This structure can be used for separations, as shown in FIGS.2A, 2B, 2C and 2D. The hydrophilic domains of surfactants arerepresented by the stippled gray circles. The hydrophobic domains of thesurfactants are represented by stippled black lines. FIG. 2A is a topview of hexagonal packing of the hexagonal phase. FIG. 2B is a side cutview of the hexagonal phase of the surfactants organized in a closepacked configuration. In both FIG. 2A and FIG. 2B, the cross-hatchedarea preferably comprises a solid, non-porous stabilization material,for example silica, an organic polymer, or a polymerizable group on someor all of the surfactants in the mesostructure. FIG. 2C is a top downview of a single surfactant cylinder in the hexagonal phase. The arrowsshow the path of molecules between the surfactants. During assembly ofthe material, hydrophobic molecules can be solvated within the cylinder.After assembly, they can remain or be removed. Both methods enabletransport through the material. FIG. 2D is a side cut view of onecylinder in the hexagonal phase. The arrows show the path of moleculesbetween the surfactants.

In the inverse hexagonal phase, they self assemble into a hexagonallattice of cylinders with the surfactant's hydrophilic domains of thesurfactants facing inward and the surfactant's hydrophobic domainsfacing outward from the cylinders towards the hydrophobic interstices.This phase may also be used for separations, as shown in FIGS. 3A, 3B,3C and 3D. The hydrophilic domains of surfactants are represented by thestippled gray circles. The hydrophobic domains of the surfactants arerepresented by stippled black lines. FIG. 3A is a top view of hexagonalpacking of the cylinders in the inverse hexagonal phase. FIG. 3B is aside cut view of the inverse hexagonal phase of the surfactantsorganized in a close packed configuration. In both FIG. 3A and FIG. 3B,the cross-hatched area preferably comprises a solid, non-porousstabilization material, for example silica, an organic polymer, or apolymerizable group on some or all of the surfactants in themesostructure. FIG. 3C is a top view of a single surfactant cylinder inthe inverse hexagonal phase. The arrows show the path of moleculesbetween the surfactants.

During assembly of the material, hydrophilic molecules can be solvatedwithin the cylinder. After assembly, they can remain or be removed. Bothmethods enable transport through the material. FIG. 3D is a side cutview of one cylinder in the inverse hexagonal phase. The arrows show thepath of molecules through the surfactant cylinder. Both hexagonal andinverse hexagonal structures allow for the separation of molecules usingthe inside of the hexagonal cylinder. The size of the pores within thehexagonal cylinder can be controlled by at least two mechanisms. Thefirst mechanism is the choice of surfactant(s) to form the structure.Surfactants cannot perfectly pack to create porosity in the intersticesbetween the hydrophilic surfactant heads or hydrophobic surfactant tailsfor the inverse hexagonal phase or hexagonal phase, respectively. As amodel of imperfect packing, a cetrimonium bromide (CTAB) micelle isroughly 50 Å in diameter but the length of an individual molecule isroughly 20 Å. This suggest a molecule as large as 10 Å in diameter couldfit through the micelle. Because a slice of a surfactant cylinder in thehexagonal phase is a two dimensional micelle, it has the same porosityas a three dimensional micelle, 10 Å. Examples of those moleculesinclude linear molecules, for example but not limited to alkanes,alkenes, alkylenes, ethers, and esters, since the terminal methyl grouphas a diameter of roughly 3.14 Å. In one embodiment, poor packing of thehydrophobic domains can be created by using one or more surfactants withlarge hydrophilic domains or large and/or branched hydrophobic domains.

The second mechanism for controlling the size of the pores within thehexagonal cylinder is the cylinders within the structure (both hexagonaland inverse hexagonal) solvating a solution during self assembly. Thesolution may or may not be extracted after self assembly. Simple methodsto extract the solvent include but are not limited to evaporation orrinsing after assembly. The amount and chemical composition of thesolution defines the pore within the cylinders. For hexagonal phasemesostructures, a hydrophobic solution will be solvated in the interiorof the hexagonal cylinders. Examples of hydrophobic solutions arealkanes, esters and ethers. For inverse hexagonal phase mesostructure, ahydrophilic solution will be solvated in the interior of the hexagonalcylinders. Examples of hydrophilic solutions are water, glycerol,ethylene glycol and other high surface tension solvents and anyaccompanying solutes.

A single surfactant or a combination of surfactants may be chosen toengineer the selectivity of the surfactant mesostructure. For example,the chain length of the phospholipids has been shown to regulatetransport across the membrane. Similarly, cholesterol is known to affectthe structure of biological membranes. For example, a one mol to one molmixture of a single chain cationic surfactant (e.g. CTAB) and an anionicsurfactant (e.g Sodium dodecyl sulfate) will form a tight packedlamellar structure because the enthalpic penalty of packing all headgroups is reduced due to the charge balance. The result is tighterpacking of the surfactants within the lamellar layer compared to lipids.Alternatively, a single or a mixture of surfactants could be used wherethe headgroups are like charged. The result is a looser packing of thesurfactants within the lamellar layer compared to lipids. Size mismatchof surfactants can also be used to affect packing. For example, onesurfactant (e.g. dimyristoyl phosphatidylcholine) could have two timesthe area of the other surfactant (e.g. CTAB). The resulting structuremay not be able to achieve a close packed structure do to the imperfectsizes of the molecules. The result of non-close packed structure islager interstitial pore size between the surfactants enabling greaterflux and less selectivity compared to lipids. Many factors affect thefinal surfactant mesostructure, including but not limited to the ratioof diameters of the surfactant in the structure, the relativeconcentrations of each of the surfactants, the representative conicshape of the surfactants, the temperature, and the thermodynamics of theassembly of the structure. For example, the packing density of lipids ismodulated by the inclusion of cholesterol. Cholesterol is a planarmolecule that sits in the interstices of the bilayer, decreasing theinterstitial space between molecules. The result is tighter packing ofthe surfactants within the lamellar layer compared to lipids.

Embodiments of the present invention include methods to createmacroscopic defects in surfactant nanostructures. In this class ofembodiments, defects are created in the nanostructure during theassembly process. In one embodiment, the film is deposited too fast,creating stripe defects due to wetting instabilities. The size of thesedefects can be anywhere from about 1 nm to about 10,000 nm.

Embodiments of the present invention include the use of surfactantmesophases other than lamellar, hexagonal, and inverse hexagonalmesophases to perform separations. Single surfactants can form severalphases, including but not limited to the lamellar phase, hexagonalphase, cubic phase, inverse cubic phase, tubular phase, and micellephase. Surfactants can be represented as conic sections. Surfactantshave shapes like pie pieces, wedges, and cylinders. The shape andconcentration of the surfactant(s) used directly affect the shape of thephase. Furthermore, mixtures of surfactants can be chosen such thatsurfactants will partition into specific phases. For example,cholesterol preferentially partitions into saturated lipid phase, andinverse cone surfactants (e.g. Didecyldimethylammonium Bromide andDipalmitoyl Phosphatidylethanolamine) will preferentially partition intothe cubic phase. The choice of a mixture of these can result in uniqueshapes and structures. The resulting surfactant phase can be lamellar,tubular, disordered, cubic, inverse cubic, or any other shape.Surfactants can be stabilized by many techniques. Sol-gel chemistry canbe used to stabilize surfactants. Stabilizing chemistries includesilica, alumina, and titania formed from chemical precursors. Precursorscan be alk-oxy precursors. For example, tetraethyl orthosilicate (TEOS)is a precursor to silica. Surfactants can also be stabilized bypolymerizing groups attached to the surfactants. For example,surfactants comprising epoxy groups can be crosslinked to stabilize themesostructure.

This embodiment of the present invention is preferably not a surfactanttemplated sol-gel material. Surfactant templated sol-gel materials usesurfactant liquid crystal mesophases to create inverse replicas ofdesirable nanostructures. With surfactant templated materials, thesurfactant is removed, typically via calcination at 400° C. Largeclasses of materials (for example plastics) are destroyed and/or damagedby the extraction protocols required to remove the surfactants. Instead,this embodiment preferably uses retained surfactant mesophases as anactive layer to enable separations. Structures no longer require thehigh temperature, aggressive solvent extraction, and/or oxidation stepto remove the surfactant, enabling the use of materials of the presentembodiment with plastics.

This embodiment of the present invention preferably uses a unique methodto make a self assembled surfactant thin film. Typical surfactanttemplated sol-gel methods require one hydrophobic compound, onehydrophilic compound, the surfactant and a mixture of water and alcoholas a solvent. The hydrophobic compound typically comprises a metalprecursor, i.e. tetraethyl orthosilicate (TEOS). The hydrophiliccompound is typically an acid or a base. In contrast, in embodiments ofthe present invention, use of a hydrophilic compound is not required toform a self assembled surfactant thin film or stabilized surfactantmesostructure.

Free Standing Surfactant-Templated Thin Films

Self assembled surfactant thin films are difficult to assemble on porousfilms. The challenge with self assembly is that the energy differencebetween the ordered and disordered states is at most approximately4.0-5.0 kcal per mol, the energy of a hydrogen bond. For comparison, thepi bond in a carbon-carbon double bond (the bond that is used in manypolymer reactions) contains 63.5 kcal per mol. Therefore differences inthe thermodynamics of assembly dramatically affect the formation of thefinal structure. For example, three Kelvin is one percent of theenthalpy of formation. An additional challenge is that the materials areassembled in the solution phase. This presents a challenge when usingporous materials since the solution will permeate the material. Once thesolution permeates the porous media, the self assembly of thesurfactants can be disrupted. Embodiments of the present inventioninclude methods to localize the assembly of surfactant mesophases toprevent their disruption, methods to chemically prepare and/or modifysurfaces to enable the creation of surfactant mesophases on desirablematerials, and methods to enable the assembly of surfactant mesophasesto create desirable structures and materials for all applications,including but not limited to separations.

While embodiments of the present invention include the use of stabilizedsurfactant mesostructures for separations, the mechanisms, methods, andapplications described in this invention area applicable to all selfassembled surfactant thin films, including biomimetic thin films,surfactant templated sol-gel materials, hybrid biomimetic sol-gelmaterials, sol-gel templated thin films, and block co-polymers. Thefollowing is a description of other applicable self assembled thin filmchemistries.

Embodiments of the present invention involve the self assembly ofsurfactant templated nanostructures from solution in physicalconfinement by two or more discreet surfaces and/or on two or moresides, enabling the creation of a unique class of materials whichpreferably comprise one or more properties of the surfactant templatednanostructure. Example surfactant templated nanostructures can be selfassembled via a physical confinement of a templating solution similar tothose described by Brinker et al. (U.S. Pat. No. 6,264,741) andreferences therein. Solutions typically comprise at least onehydrophobic compound, one hydrophilic compound, and at least oneamphiphilic surfactant. Classically, as solvent is removed, the solutionmay exceed the critical micelle concentration of the surfactant toinduce the formation of the nanostructure in the physically confinedvolume. The solution may include initiators which are triggered viaexternal electromagnetic field, temperature, and/or aging. Afterformation, the material can be washed to remove excess solution or toextract surfactant. Surfactant can also be removed via calcinations. Inother words, as solvent evaporates, the silica condenses around thesurfactant structure, producing a three dimensional inverse replica ofthe surfactant phase. This method enables pore sizes to be controlled,which is particularly useful for separations.

Structures formed by biosurfactants, (e.g. phospholipids) (see, forexample, U.S. Patent Publication No. 2007/0269662) can be produced in alamellar phase to block transport or via the incorporation of transportregulating molecules such as ion channels to define the pores of thematerial, typically without removing the surfactant. This structure is abiomimetic surfactant nanostructure (“BSNS”), which has a surfactantdefined structure similar to previously described surfactant templatednanostructures, and optionally comprises the additional function of thesurfactant phase partially or completely solvating structures thatactively or passive regulate transport (“transporters”) across themembrane. By co-assembling these films with components of or intoelectrochemical cells as electrolytes, they have the potential to reduce‘crossover’ of aqueous molecules and/or ions. By assembling these filmsbetween Nafion membranes, a free standing surfactant templated membranecan be created. Many molecules, macromolecular assemblies, polymers,proteins, etc are solvated and can act as transporters in a lipidbilayer. Any surfactant(s), including but not limited to natural lipids,may be used including surfactants used to purify proteins, membraneproteins and ion channels. The simple nature of this method enablessimple scaling into commercial manufacture and existing post manufacturemembrane process. Hierarchical structures produced according to thepresent invention have applications include optics, separations, fuelcells, energy storage, energy conversion, chemical manufacture, ionexchange, purification, electrochemistry, surface coatings,sequestration, biosensing for medical diagnosis and/or environmentalmonitoring, chemical and biological warfare agent sequestration, andactuator development. Physical confinement can be used to integrateBSNS's with size exclusion membranes, ion exchange membranes, gasdiffusion layers, catalysts and/or other materials used inelectrochemical cells, optionally via multiscale self assembly.

Although the use of natural lipids has been demonstrated for surfactanttemplated nanostructures which include transporters, other surfactantsmay optionally be used. For example, surfactants already used forpurification of membrane proteins have the potential to simultaneouslytemplate nanostructures and embed ion channels. Other lipid mimeticsurfactants could be used to increase stability, resistance or otherphysical properties of the resultant nanostructure. Examples ofsurfactants are Brij, sodium dodecylsuphate, anionic surfactants such assodium laureth sulfate, perfluorooctanoate, perfluorooctanesulfonate, orsodium dodecyl sulfate, cationic surfactants such as cetyltrimethylammonium bromide, or zwitterionic surfactants such as1,2-di-O-tetradecyl-sn-glycero-3-phosphocholine. Any zwitterionicsurfactant is of particular interest especially if the surfactantspontaneously self assembles into vesicles. Transporters of interest maycomprise either natural or synthetic channels. One or more channels canbe included in the surfactant templated nanostructure as transporters tocontrol permeability, transport, and convert molecular gradients intoother forms of energy. Channels can be passive to enable passiveselective membrane transport (e.g. gramicidin), active to enablemembrane transport against free energy potentials (e.g. rhodopsin),active to allow passive membrane transport under selective conditions(e.g. voltage gated channels), and/or active enabling molecularconversion using passive membrane transport (e.g. ATPase). Furthermore,Transporters can work in conjunction when activated by external stimuliincluding electromagnetic field, pressure, and chemical recognition.Transporters can actively drive transport against free energy gradients.Materials with biomimetic surfactant nanostructures assembled betweenporous surfaces are of particular interest for dialysis, separations,electrochemical cells, fuel cells, and batteries. These channels cancreate membranes with sub nanometer pore sizes for a variety ofelectrolysis applications including fuel cells. Non biologicaltransporters can be included in biomimetic surfactant nanostructuresincluding but not limited to carbon nanotubes. Many molecules,macromolecular assemblies, polymers, proteins, etc are solvated in alipid bilayer. This class of structures can regulate transport across alipid membrane via selective regulation of passive diffusion or activeregulation. Active enzymes or synthetic variants could be included inthe membrane to produce a high voltage batteries, chemo-electric energyconversion, photo-chemo energy conversion, and/or photo-electric energyconversion.

Embodiments of the present invention utilize surface functionalizationchemistry to enable and/or enhance the assembly of surfactantmesophases. Surface functionalization chemistry changes the surfaceproperty or properties of a material without changing the bulkproperties. An example of surface functionalization chemistry is thechemistry to assembly a self assembled monolayer (SAM) ofoctadecyltrichlorosilane on a silicon wafer. The surface of the waferbecomes hydrophobic but the mechanical and optical properties remain thesame. The interaction between the surfactant and the chemically modifiedsurface drives the self assembly and imbues stability to the thin filmafter assembly. This has been well studied in the assembly of a selfassembled monolayer on a solid surface. For example, a single molecularlayer of octadecyltrichlorosilane can be assembled on a silicon wafer tomake the surface hydrophobic. Previous studies with surfactant bilayers(i.e. supported lipid bilayers) have demonstrated the effect ofsubstrate preparation on the physical properties of the final material.Embodiments of the present invention enable the assembly of surfactantmesophases on solid and porous supports. Typical surfacefunctionalization chemistries include surface grafting, covalent surfacemodification, surface adsorption, surface oxidation, surface ablation,and surface rinsing. Chemicals can be deposited in the liquid phaseand/or the vapor phase. Molecules that can be covalently attached to asurface including but are not limited to silanes, organics, inorganics,metals, and metal oxides. Metal oxides are of interest because they candramatically increase the surface tension of the material. For example,the assembly of an alkyl silane can make a hydrophilic surfacehydrophobic. The surface modification can also enable the ordering andassembly of the surfactants. For example, calcium can enhances theassembly of surfactants; doping calcium into the supporting material canreduce the defects in the surfactant mesophase. For another example,silica can stabilize the hydrogen bonding network of lipids. In oneembodiment, surface functionalization chemistry is used to coat apolyethersulfone ultrafiltration membrane with silica. The result isenhanced rejection of solute by the surfactant mesophase assembly, aresult of enhanced assembly in the ordered, lamellar phase.

Embodiments of the present invention utilize localization of theassembly of surfactant mesostructures, which is particularly useful forpreventing the wetting of a porous surface by a self assembly solution.If the self assembly solution wets the porous surface, the mesostructuremay be disrupted. One localization mechanism is to drive the surfactantsolution through a phase change at an interface where assembly is tooccur using the addition of solvent and/or solute. In one embodiment,the porous material is first substantially saturated with an aqueoussolution (Solution 1). Second, a self assembly solution comprising TEOS,dimyristoyl phosphatidylcholine (DMPC), ethanol and water (Solution 2)is deposited on the surface. DMPC is preferably in the gas phase inSolution 2 as it is deposited on the surface. Solution 1 and Solution 2mix at the surface of the porous material. The DMPC is driven to thelamellar phase due to the increase in water concentration. In thisembodiment, the self assembly of DMPC is preferably visualized by thesolution rapidly increasing in viscosity and opacity. This processenables rapid self assembly and can be repeated to assemble multiplelayers. For example, after the deposition of Solution 2, another coatingof Solution 1 followed by Solution 2 could be applied.

This mechanism is illustrated in FIG. 4. The porous support is wet by asolution (Solution 1). A subsequent Solution (Solution N) is introduced.Surfactants in Solution 1 or Solution N are driven through a phasechange by the addition of Solution N and/or Solution 1 respectively.After the assembly at one or more levels of the solute, a second set ofsolutions (Solution 1 and Solution N) can be introduced to repeat theprocess and/or add additional coats. Surfactant mesophase self assemblyoccurs at the interface between Solution 1 and Solution N. The finalmaterial is a free standing hierarchical material, preferably adhered toa support, that has some or all of the properties of both the selfassembled surfactant mesostructure and the support. This technique isparticularly useful for assemblies on porous supports. Examples of suchproperties that may occur in the resulting material include control oftransport of ions and molecules, increase thin film durability, and/orprotection and/or encasement of thin films with well known antimicrobialnanoparticles.

In one embodiment, a porous membrane is wet with a polar solvent. Inthis embodiment, the polar solvent is Solution 1. The polar solvent maycomprise water, ethylene glycol, glycerol or a mixture thereof. Thepolar solvent may or may be acidic or basic. Subsequently, an aliquot ofself assembling solution in organic solvent is deposited. In thisembodiment, the organic solvent is Solution N, which preferablycomprises surfactants. In this specific embodiment, Solution N comprises5 wt % tetraethyl orthosilicate (TEOS), 1 wt % DMPC in organic solvent.The organic solvent may comprise, but is not limited to, one or morealchohols, alkanes, esters, ethers, or a mixture thereof. At theinterface of the two solvents, the surfactant is driven through a phasetransition to form a surfactant mesostructure by the presence ofSolution 1. Finally, the solvents evaporate driving the assembly ofsilica to stabilize the surfactant mesostructure at the interfacebetween Solution 1 and Solution N. FIG. 5 illustrates a slab model ofthe structure, a schematic of the structure, and a images of ahydrophilic Teflon membrane before (LEFT) and after (RIGHT) interfacialassembly.

The assembly within the self assembled film and the assembly of the thinfilm with a porous surface make this a multiscale self assembledmaterial. As shown in FIG. 5, on the microscale is the assembly of thetwo films A and B. In this embodiment, A is a nanostructured thin filmand B is a porous membrane. On the nanoscale is the assembly ofalternating lamella of silica and lipid bilayers illustrated in both Aand enlarged in C. Within the lipid bilayer is an optional ion channel,gramicidin (the beta ribbon structure in C). In the photograph, the leftside is a membrane before coating and on the right side is a membraneafter coating. The membranes are hydrophilic PTFE with 0.1 micron poresand are nominally 47 mm in diameter. The membrane on the right is tintedyellow from the natural color of the lipids, Soy PC (95%) from AvantiPolar Lipids (Alabaster, Ala.), used in the embodiment described above.

Other methods can be used to localize the self assembly. Self assemblycan by induced through changing one or more thermodynamic variablesincluding temperature, pressure, volume and/or the number of moleculesand/or by the application of electromagnetic field. External stimuliincluding optical energy, ultraviolet light, electrophoretic fields,and/or alternating current electric fields may direct the assembly toalign molecules, pores, or channels. Both optical and electricalexternal fields can direct the assembly of model, colloidal systems.

An additional layer can be deposited on a precursor layer or layers.Those layers can be cured. The additional layer can be symmetric orasymmetric. A primer layer may be used to enable improved assembly ofthe second layer. An embodiment of such a structure is presented in FIG.37, which depicts an embodiment of a lamellar structure with threelayers of distinct self assembled material. In this embodiment, eachlayer is a z-dimensional nanostructure. One or more of the layers mayoptionally not be lamellar in the multilayered structures. Layer A is az-dimensional lamellar structure comprising a mixture of single chainsurfactants. Layer B is a z-dimensional lamellar structure comprising asingle dumbbell shaped molecule. Layer C is a z-dimensional lamellarstructure containing a mixture of dumbbell molecules and single chainsurfactants. Although in this figure each layer is represented by threelamellae, a layer may comprise any number of lamellae. One method tocreate such a structure is to assemble a single self assembled layer viaany method, including the ones described herein, cure the layer, thendeposited another layer of any composition, including the compositionsdescribed herein, via any method, including those described herein. Thisprocess can be repeated as many times as desired.

Physical Confinement Manufacturing Methods

Embodiments of the present invention utilize physical confinement of asurfactant self assembly solution which preferably simultaneouslytemplates the film structure, drives film assembly, and assembles thethin film with the surfaces used for physical confinement resulting in asingle unique material. During physical confinement based self assembly,both multiscale assembly and hierarchical assembly can occur. Inembodiments of the present invention, there can be many scales ofassembly, such as self assembly on the nanoscale within thenanostructured thin film and self assembly on the macroscale between thenanostructured thin film and the surface(s) used for physicalconfinement. In embodiments of the present invention, there can be manylevels of assembly including intermolecular assembly (e.g.surfactant-surfactant assembly), molecular assembly (e.g. silicacondensation), material assembly (e.g. the thin film assembling with thesurfaces), the assembly based upon interaction of the surfactant withthe solvent, and the assembly based upon the interaction of the surfaceswith the self assembly solution.

The interplay of the physical and chemical topology of the confiningsurfaces, the method used to induce assembly, and the mixture of theself assembling solution all can determine the final structure of thematerial. Unique classes of surfaces can be integrated with surfactanttemplate nanostructures via the present invention, including but notlimited to surfaces comprising one or more of the followingcharacteristics: solid, porous, chemically layered (e.g. a thin filmself assembled on a surface or a chemical spin coated on a solidsurface), physically layered (e.g. one or more surfaces on top of asolid surface), comprising macroscopic features, comprising microscopicfeatures, comprising non-radially symmetric surfaces, an inability toform a stable meniscus, more than two dimensions of physical features,and/or non homogeneous surface chemistry. Surfaces used for assembly canbe designed for modification and/or removal after assembly withoutdestroying the remaining material such that surfaces can be removedafter assembly without complete annihilation of the material.Embodiments of the present invention preferably comprise robust methodsto rationally design, simultaneously assemble, template and integratesurfactant templated nanostructures. Hierarchical assembly can producematerials in a single step that normally would require multiple steps,e.g. membrane electrode assemblies, sensors, or switches.

Two important aspects of the assembly of self assembled surfactant thinfilms on porous plastic supports are the surface functionalizationchemistry of the support and the interfacial polymerization method.Taken together with the physical confinement method, these enable theformation of the final material, a self assembled surfactant thin filmat the surface of a porous plastic support.

Embodiments of surfactant mesophases of the present invention canperform separations. The assembly method and the resulting biomimeticsurfactant nanostructure are illustrated in FIGS. 6A and 6B. In thisembodiment, two membranes or porous surfaces are prepared as supportsfor a self assembly solution using one of a variety of protocols, whichare defined under “Material Preparations” in the examples section.Protocols of importance include but are not limited to surface cleaningwith solvents, surface oxidation, and/or surface chemical deposition.The material was composed of two PES membranes integrated with abiomimetic surfactant templated sol-gel thin film. Two polyethersulfone(PES) membranes were soaked in 18.2 MΩ water then placed on twodifferent planar Teflon pieces, used for physical confinement. Analiquout (˜500 ul) of 10 wt % of 10 mol DLPC: 1 mol gramicidin in stocksilica solution was dispensed via micropipette on one of the PESmembranes. The second Nafion membrane backed by Teflon was used tosandwich the BSNS solution between the two membranes, as shown in FIG.6A. The pieces were allowed to sit together in contact. Samples weredried at room temperature for greater than one hour before being heatedto 80° C. for over 3 hours. Finally, to model the assembly of a membraneelectrode assembly, some samples were heated to over 130° C. for 15minutes. After cooling the samples slowly, the Teflon materials wereremoved to produce free standing membranes, as shown in FIG. 6B. In thisembodiment, Teflon was used for physical confinement. Alternatively, anysolid surface can be used, including metal, plastic, ceramic, glass, andorganic (e.g. wood). The membrane is 4 cm×4 cm. The confinementsimultaneously drives assembly and integrates the resultant film withthe physical confining assembly.

FIG. 7 is a schematic of the resulting biomimetic surfactantnanostructure structure in this embodiment: two supporting porousmaterials sandwiching a lamellar nanostructure with alternating silicalayers and lipid bilayers. The material is a multiscale self assembledmaterial. Microscale assembly is of the three films (A, B, and C). Inthis embodiment, A and C are porous membranes and B is a nanostructuredthin film. Nanoscale assembly is the lamellar alternating silica layersand lipid bilayers (B and D). Within the lipid bilayer is the ionchannel, gramicidin (the beta ribbon structure in D). Alternatively,only one of supporting porous materials (A or C) may be used.

Physical confinement also enables the use of roll coating. A selfassembly solution is sandwiched between a porous support material and acylindrical roller. The temperature of the roller can be controlled tocontrol the evaporation rate of the solution. The solution can bedirectly applied to the roller. The roller can be applied more than onceto the self assembly solution on the porous material. The roller canpush or pull the support material through one or more process steps. Thesandwich enables an even deposition of material on the porous supportmaterial.

FIGS. 8A, 8B and 8C show a several different physical confinementmethods: confinement by two solid surfaces (A), confinement of the selfassembly solution and two porous materials (B) and a prototypehigh-throughput device and system to assemble many materials with uniquechemistries simultaneously (C). The high-throughput device is a Teflonplate with holes in it and a solid piece of Teflon sandwiched a piece ofNafion. Surfactant templating solution was added to each well followedby a Nafion membrane and a piece of Teflon such that the Nafion wassupported by Teflon. The material was self assembled in physicalconfinement using a multistep drying protocol. After assembly, the setupwas disassembled to retrieve the new, freestanding membrane material.The central images of FIGS. 8A-8C are of the system during assembly. Thebottom images of FIGS. 8A-8C are of the disassembled structure afterassembly of the material.

FIG. 8 illustrates several different examples of physical confinement ofsurfactant templated sol gel solution and the resulting materials. Asurfactant templated sol gel solution was deposited on a freshlyoxidized silcon wafer. Afterwards, a silica coverslip with a selfassembled monolayer of octadecyltrichlorosilane was used to sandwich thesolution between the two discreet surfaces. Once drying was complete, athin film remained on the surface after the removal of the coverslip.FIG. 8A shows a hydrophobic and a hydrophilic surface sandwiching asurfactant templated sol gel solution. After drying the film, thehydrophobic surface was removed. The images are of the film afterremoval.

FIG. 8B shows a schematic of another embodiment of a physicallyconfining “sandwich”. To assemble the membranes, two Nafion membraneswere soaked in silica precursor solution then placed on two differentplanar Teflon pieces. An aliquout (˜100 μl) of 5 wt % BSNS solution wasdispensed via micropipette on one Nafion membrane. The second Nafionmembrane backed by Teflon was used to sandwich the BSNS solution betweenthe two membranes. (Alternatively, in other embodiments the membranesmay be supported by any solid surface or gas diffusion layers (GDLs) ona solid surface.) The surfaces were held together by alligator clips.Samples were allowed to dry at room temperature for greater than onehour before being heated to 80° C. for over 3 hours. Finally, to modelthe assembly of a membrane electrode assembly, some samples were heatedto over 130° C. for 15 minutes. After cooling the samples slowly, theTeflon surfaces were removed to produce free standing membranes.

The resulting membrane was stable to shear forces that are generated byrubbing the membrane with two fingers and to any strain forces inducedby peeling with tweezers. No precautions were necessary to prevent themembranes from being damage during in typical laboratory typical of aNafion membrane. The center image is of a typical sample membranewithout the surfactant in the templating solution after assembly. Thefinal material is a translucent white. The bottom image is of arepresentative free standing BSNS after assembly with the surfactant inthe templating solution. The membrane has a yellow color unique tolipids assembled into a BSNS in physical confinement. Lipids evaporatedon a surface do not yellow after a similar heat treatment. Due to thecomparable periodicity of the surfactant templated nanostructure and thewavelength of visible light, the yellow color is likely a result ofscattering from the lamellar nanostructure. These membranes were stabledespite dehydration, up to 130° C. heat treatment, and pressuretreatment via two solid surfaces and alligator clips.

FIG. 8C shows a modification of FIG. 8B, illustrating a prototypehigh-throughput device and system to assemble many materials with uniquechemistries simultaneously. A Teflon plate with holes in it and a solidpiece of Teflon sandwiched a piece of Nafion. Surfactant templatingsolution was added to each well followed by a Nafion membrane and apiece of Teflon such that the Nafion was supported by Teflon. Thematerial was self assembled in physical confinement using a multistepdrying protocol. After assembly, the setup was disassembled to retrievethe new, freestanding membrane material. The center image is of thesystem during assembly. The bottom image is of the disassembledstructure after assembly of the material.

The following embodiments of the present invention demonstrate howsurface functionalization chemistry enhances the assembly of thesurfactant mesostructure, which can be observed by the improvedrejection of solute. The surfactant mesophases are used as reverseosmosis membrane to separate methanol from water. FIGS. 9A and 9B showthe effect of surface preparation techniques versus the flux andmethanol rejection of the membrane. Here, performance is defined by twometrics: methanol rejection percentage and solution flux. Methanolrejection percentage is one minus the ratio of the permeate methanolconcentration to the feed methanol concentration. The rejectionpercentage of 25% v/v methanol (Ref/0) as a function of the PreparationMethod of the porous surfaces used to support the free standingsurfactant templated thin film is shown in FIG. 9A. Solution flux is thevolume of solution per time for constant area through the membrane,shown for each preparation method in FIG. 9B. Three representativemethods were examined: chemical cleaning (Rinse Clean), surfaceoxidation (UV Clean and H2O2 Boil), chemical deposition (TEOS), andcombinations thereof. In this embodiment, the self assembly solutioncontained 10 wt % of 10 mol DLPC: 1 mol gramicidin in stock silicasolution. In this embodiment, the self assembly solution was sandwichedby two 0.03 micron polyethersulfone (PES) membranes. The effective areaof the membrane was 1.13 cm². Separations were performed at 5 PSI.Methanol separation was not observed in control experiments with thestock PES membranes. Because the pore size of a PES membrane (30 nm) ismuch greater than the diameter of methanol (0.41 nm), rejection ofmethanol was not expected. Rejection of methanol (FIG. 9 samples: UVClean UV Clean Net, H2O2 Boil, H2O2 Boil TEOS) demonstrates thesurfactant mesophase membrane's ability to perform a small moleculereverse osmosis separation.

Furthermore, FIG. 10 compares the flux of pure water and 25% w %/w %methanol in water through a single free standing biomimetic surfactantmesophase membrane, assembled from a 10 lipid wt % solution comprising10:1 DLPC to Gramicidin between two PES membranes prepared using UVclean, at 5 psi-15 psi. The >50% reduction in the flux of the 25 w %/w %methanolic solution vs. pure water flux at all pressures is a result ofconcentration polarization, an increase in solute (methanol)concentration at the membrane surface due to the selectivity of themembrane for water. Furthermore, as the flux increases with pressure,the relative difference between the flux of 25% w %/w % methanolsolution and pure solvent (18.2 MΩ water) increases. This is expectedsince the effects of concentration polarization are a function ofmembrane flux; that is, more methanol is accumulated at the surface whenthe flux of the solution through the membrane increases.

Embodiments of the present invention use the conformal coating of selfassembled surfactant thin films on hollow fiber membranes.Ultrafiltration and microfiltration membranes can be constructed ashollow cylinders. In the wall of the fiber are pores typically rangingin size from about 30 nm to hundreds of microns. In one embodiment, ahollow fiber is coated with silica using the H2O2 Boil TEOS method. Thefiber is then rinsed with water. Afterwards, the fiber is filled withsurfactant self assembly solution. After filling the fiber withsurfactant self assembly solution it is sealed at both ends. The solventis allowed to evaporate through the pores of the membrane. After heatingfor one day in an oven at 80° C., the inside of the fiber is preferablyrinsed with water. The inside of the fiber is coated by the surfactantself assembled thin film.

Materials constructed in accordance with embodiments of the presentinvention preferably integrate a self assembled nanostructure and/orthin film with surfaces used for confinement; the resulting materialthen preferably has some or all of the properties of both the selfassembled nanostructure and the surfaces. Examples of such surfaceproperties that may occur in the resulting material include control oftransport of ions and molecules, increase thin film durability, and/orprotection and/or encasement of thin films. Surfaces used for assemblymay be removed or modified after assembly without annihilating thematerial.

Although theory suggests that surfactant templated nanostructures canproduce useful structures for separations, the challenge of defect freeassembly has prevented them from being so used. By employing one or moremembranes to physically confine a surfactant templated nanostructureself assembled solution, the resultant selectivity of the final materialcan be a composite of the integrated membrane(s) and the nanostructuredthin film. In one embodiment, a biomimetic thin film with highconductivity and high selectivity can be assembled on a Nafion film.Because of the thin nature of the film, the conductivity of the thinfilm is negligible compared to Nafion. The structure of the film makesthe conductivity of other ions more difficult. The biomimetic thin filmis a z-dimensional crystal of lipid bilayers and sol-gel silica. Withineach lipid bilayer is an ion channel, gramicidin. Because of thecombined resistance of the resultant material, a short circuit throughthe membrane caused by a pinhole defect in the biomimetic film is notpossible. Furthermore, the final material can be free standing, e.g. itcan be handled, moved, manipulated and applied without additional theneed for special techniques and/or equipment. Hierarchical structuresproduced in this method have applications in optics, separations, fuelcells, electrochemistry, surface coatings, sequestration, biosensing formedical diagnosis and/or environmental monitoring, chemical andbiological warfare agent sequestration, and actuator development.

There are many different configurations to physically confine asurfactant templated sol gel solution, such as those comprising selfassembly of model colloidal systems. One configuration of physicalconfinement is introducing a surfactant self assembly solution betweentwo or more discreet surfaces. One example is a surfactant sol gelsolution sandwiched between two planar surfaces. One configuration ofphysical confinement is introducing a surfactant self assembly solutioninto a volume that has two or more sides. An example is a single foldedsurface, which has three interior sides: the top surface, the bottomsurface, and the surface of the fold. Another configuration is thephysical confinement of a self assembly solution by a single surfacewith three dimensional topography, such as surfaces with no symmetricaxes, molded surfaces, microfabricated surfaces, or etched surfaces. Inthis example, the sides of the single three dimensional surfaces confinethe surfactant templated sol gel solution.

In FIGS. 11A and 11B, BSNS membranes prepared from a stock and a dilutedself assembly solution are compared. The stock membrane was preparedwith a typical lipid solution 10 wt % of 10 mol DLPC: 1 mol gramicidinin stock silica solution. A dilute membrane was prepared with a typicallipid solution 10 wt % of 10 mol DLPC: 1 mol gramicidin in stock silicasolution diluted 1:1 v %/v % with ethanol. Both membranes were assembledbetween two PES membranes prepared via UV Clean. The effective area ofthe membranes was 2 cm². With a lower concentration of BSNS selfassembly solution and constant area of the supporting membrane andconstant volume of the self assembly solution, there is less material toassemble into the BSNS film. The membrane produced with the diluted selfassembly solution (UV Clean Dilution 1:1) behaves likes a thinnermembrane compared to the membrane produced with the stock self assemblysolution: it has lesser methanol rejection (FIG. 11A) and greatersolution flux (FIG. 11B) than a 10 wt % of 10 mol DLPC: 1 mol gramicidinin stock silica solution assembled between two PES membranes preparedvia UV Clean (Standard Biomimetic surfactant nanostructure).

In one embodiment of the present invention, the thickness of theresultant thin film is controlled by physical confinement of themembrane in a groove. A one dimensional cell is constructed preferablycomprising at least one linear groove running the length of the cell.The membrane preferably sits flat at the bottom of the groove. Themembrane is preferably first coated with water. Then, surfactant selfassembly solution is placed on the membrane. The volume of the solutionis preferably chosen such that it exceeds the height of the groove. Theexcess volume is then preferably removed with a blade, a straight edgeand/or a roller. The thickness of the final film is determined by thedepth of the groove and the solids contents of the surfactant selfassembly solution. FIG. 12 shows the decrease in permeability of amembrane self assembled in physical confinement with a linear groove(Groove) compared to a membrane self assembled in physical confinementbetween a roller and a flat piece of Teflon (No Groove). Two 20 wt %DLPC solution were self assembled on a UV Clean 0.1 micron PES membrane.The solution was self assembled using the interfacial method and byphysically confining the solution between a roller and the porousmembrane. Before assembly, one membrane was placed at the bottom of agroove. The depth of the groove was half a millimeter. The result was anincrease in the volume of self assembly solution that coated themembrane. The membranes were loaded into a dead end cartridge. The waterpermeability was measured at 5 PSI. When the water permeability wasmeasured, the material that was assembled in the groove had a lowerpermeability than the material assembled on a flat surface. The increasein confining volume of the membrane self assembled in a groove resultsin a thicker stabilized surfactant mesostructure thin film. The increasein thin film thickness results in decreased thin film permeability.

One potential confinement scheme comprises a surfactant templated thinfilm assembled into complex three dimensional geometries, such as theself assembly of colloids in physical confinement where one or moresurfaces has asymmetric three dimensional topology (Yang et al, “Opalchips: vectorial growth of colloidal crystal patterns inside siliconwafers”, Chem. Commun. 2000, 2507-2508). For example, a surface can be amolded polydimethylsiloxane (PDMS) surface with three dimensionaltopology, or alternatively an etched silicon wafer. The surfactanttemplated nanostructure preferably assembles preferentially in thegroves due to solvent evaporation from between the sides of the threedimensional solid surface(s). This scheme templates and integrates thesurfactant templated nanostructure with a three dimensional surface.Some embodiments comprise localize assembly within channels, and/ornanoscale patterns for microfluidic and optical applications, Thisarchitecture preferably gives the thin film the stability of the solidsurface and the access to through transport that is not possible withother assembly methods. The preferable result is a multiscale selfassembled material for which the surfaces protect and scaffold thenanomaterial and the nanomaterial adds a new functionality. Anotherphysical confinement scheme combines chemical patterning with physicalconfinement to enable self assembly and patterning of the surfactanttemplated nanostructure. This scheme has been demonstrated to selfassemble and pattern model colloidal systems (Brozell et al, “Formationof Spatially Patterned Colloidal Photonic Crystals through the Controlof Capillary Forces and Template Recognition”, Langmuir, 21, 2005,11588-11591). In this scheme, the thin film assembly is driven by thephysical confinement of two surfaces. One or more moieties on thechemically patterned surface(s) cause the thin film to be unstable. Postassembly, the thin film is destroyed in the unstable regions. In oneexample, a thin film could be assembled between a patterned wettabilitysurface and a hydrophilic surface. There are many methods to patternsurface wettability. One example is to create a uniformly hydrophobicsurface using a hydrophobic self assembling silane then selectivelyremove the silane with deep UV lithography. Two examples of hydrophobicsilanes are octadecyltrichlorosilane (CH₃(CH₂)₁₇SiCl₃, OTS) (90%Aldrich) and fluoroalkyltrichlorosilane (CF₃(CF₂)₁₀C₂H₄SiCl₃, 1,1,2,2,tetramethylene fluorodecyl tricholorosilane, FDTS). They are assembly byallowing a freshly oxidized surface to incubate in 2.5 mM solution (100ml vol.) with anhydrous hexadecane (99% Sigma-Aldrich) or HPLC-gradetoluene (99% Sigma-Aldrich) is preferably used as the solvent. Allsilanisation reactions are preferably carried out in glass containersunder nominally dry ambient conditions (relative humidity <20%). After60 min incubation, samples are preferably removed from the solution, thesurface is rinsed extensively with chloroform and acetone, and driedunder a stream of nitrogen. Silanes are preferably lithographicallyremoved via a combination of short-wavelength UV lithography (187, 254nm) using an ozone-generating medium pressure Hg lamp (UVP, Inc)enveloped in quartz sheath and a quartz lithographic mask with chromefeatures. Other methods for patterning wettability include micro contactprinting. Patterned surfaces include those surfaces displaying a patternof electrodes.

This invention enables the assembly of self assembled thin filmstechnologies, including but not limited to stabilized surfactantmesostructure thin films and surfactant templated sol-gel thin films, onmany surfaces unable to be used with standard techniques of dip coatingand spin coating. Many surfaces can be used for physical confinement,such as Teflon, plastic, acrylic, Nafion, ceramic, silica, silicon, asemiconductor, an oxide, gold, glass, metal, polymers, poly di-methylsiloxane (PDMS), molded polymers, membranes, poly carbonate membranes,size exclusion membranes, ion exchange membranes or graphite. Thesesurfaces can be planar, radially or spherically symmetric (e.g. ballbearings), cylindrically symmetric (e.g. rollers), have two dimensionalphysical and/or chemical topology, and/or have three dimensionalphysical and/or chemical topology. A surface may be a roller or a pressused in manufacturing. Surfaces can be layered, including one or morechemical and/or physical layers. Chemical layers include but are notlimited to self assembled layers, physically absorbed layers, anddeposited layers (e.g. Langmuir Blodgett assembled layers or spin coatedlayers). Physical layers include but are not limited to: microporoussurfaces, macroporous surfaces, layers with desirable electricalproperties, and layers with desireable optical properties.

Porous surfaces, such as Nafion (of any thickness, including but notlimited to Nafion 117), ion exchange membranes, carbon felt, carboncloth, cellulose membranes, poly amide membranes, polyvinyl membranes,poly carbonate membranes, other membranes, gas diffusion layer, gasdiffusion electrode, metals, Teflon, plastic, silica gels, Nafion,carbon cloths, Ultrex™ (Membranes-International Ltd.), Neosepta® AHAmembrane (Eurodia Industrie SA), size exclusion membranes, and/or gasdiffusion electrodes can be used. For porous materials, the physical andchemical topology of the material and its pore size typically define thefinal structure and function of the material. Pores sizes can be eithermacroscale or microscale or both. A macroscale pore allows for thepermeation of the surfactant through the material, preferably assemblingthe surfactant templated nanostructure within the membrane. A microscalepore structure typically prevents or limits the permeation of surfactantthroughout the material, preferably assembling the surfactant templatednanostructure on or near the surface of the membrane. The pore sizecharacterization (macropore vs micropore) is preferably defined by thephysical chemistry of the surfactant, not the geometry of the pore.Surfactants have a coherence length. Thus, a material may havemacroscale pores for one surfactant solution and microscale pores for adifferent surfactant solution. For example, lipids vesicles at 1 mg/mlconcentration in aqueous conditions will self assemble on top of acolloidal crystal with 45 nm pores, in which case the surface ismicroporous. Triton-X, a different surfactant, will permeate a colloidalcrystal with 45 nm pores, in which case the surface is macroporous.

Particular embodiments of this invention include the automatedmanufacturing of the surfactant self assembled thin films includingstabilized surfactant mesostructures, biomimetic surfactantmesostructures and sol-gel templated mesostructures. This inventionincludes many automated or mass production manufacturing techniques forthese films including spray coating, painting, inkjet printing, rollcoating, reverse roll coating, blade coating, gravure coating, gapcoating, immersion coating, curtain coating, metering rod coating, slotcoating, air knife coating and knife coating. FIG. 13 illustrates arepresentative, but not limiting, configuration of an automated systemto manufacture self assembled thin films on membranes and othermaterials. Each Point, labeled with a letter A-H, may or may not beincluded in a manufacturing system. Point A is where the deposition ofthe self assembly solution occurs. Point B and Point C are pre and postprocessing steps respectively. In these steps the material may besubject to one, some, or all of the following: changes in temperature,exposure to an oxidative environment (e.g. ozone producing UV light,ozone gas), deposition of chemicals (e.g. to promote adhesion), chemicalrinse or cleaning, the addition or removal of material, chemicaletchants, pressure, and/or tension, etc. Point D is the material feed.This material can be anything including, but not limited to, a membrane,a PTFE membrane, a PES membrane, a PVP membrane, a plastic, carboncloth, carbon felt, or any other material. Before assembly, the materialcan be washed in water and/or other solvents, temperature treated,placed in an ultra sonic bath, and/or have other molecules deposited onit. Point E is the final material. Material at this point can be, but isnot limited to, a roll of membrane, a spiral membrane cartridge, or anintermediate point in a larger process. Point F is the material feedgoing through manufacturing. Point G is separate material being fed intothe final material at Point E. Point H is a separate material whichundergoes one, some, or all of the processing of the material in Point Fand is fed into the material in Point E. In some instances, the materialfrom either Point F or Point G will induce physical confinement of theself assembly material deposited on Point F and rolled into point E. Theorientation of this device is only exemplary, and the elements may bere-arranged in many suitable orientations with respect to the verticaldirection for carrying out the method steps shown. Additionalconventional supports, such as guides, rollers, and the like, may beused to support, tension, turn, and/or twist the feed membrane and thebiomimetic surfactant nanostructure.

Certain embodiments of methods of the present invention comprise one ormore annealing steps after the deposition of the surfactant selfassembly solution. The addition of a specific solution enables some ofthe surfactant to escape from the ordered phase into the disorderedphase. The solution is preferably chosen based on the phase diagram ofthe multi-component mixture which includes at least two solvents and thesurfactant. The subsequent addition of a second specific solution and/orevaporation drives some of the surfactant into the ordered phase. Thesecond solution is also preferably chosen from the multi-component phasediagram such that the surfactant is driven into the desired orderedphase. The ordered phase of the surfactant after any of the annealingprocesses can be unique, and the surfactant can be in another phasewithin the material. The process may be repeated with all three or anycombination of the steps one or more times. This process anneals thesurfactant mesophase to remove defects and excess surfactant and/or toadd an additional phase of surfactant. This annealing process is similarto the annealing of metal or glass to reduce the likelihood of materialfracture. In FIG. 14, the permeability of two membranes are comparedwhere the only difference is the annealing step. The membranes are UVClean 20 wt % 10:1 DLPC to Gramicidin on 0.1 micron PES membrane. Thepermeability of the membranes was measured using a home built cross flowmembrane test cell. The pressure drop across the cell was 55 PSI. Theannealed membrane shows higher permeability with no loss in rejection tofluorescein salt.

Embodiments of the present invention allow for the deposition on bothsides of the material to create symmetric membranes. When theinterfacial self assembly method is used, resulting in an asymmetricmembrane; that is a membrane with a thin film on only one side. Theprocess to deposit a self assembled surfactant thin film can be repeatedon the other side of the porous material. A schematic comparingasymmetric and symmetric membranes is shown in FIG. 15. In oneembodiment, a UV Clean 20 wt % DLPC on 0.1 micron PES membrane wasassembled. After curing the membrane for one day at 80° C., the processwas repeated on the other side of the PES membrane. A forward osmosisexperiment was conducted between two 10 L buckets of water. Theconductivity of the feed was less than 1 μS/cm. The conductivity of thebrine was 110 mS/cm. The solute in the brine was NaCl. The pressure dropwas 5 PSI from the feed to the brine. The membrane area was 3 squareinches and it was tested in a homebuilt cross flow test cell. Asexpected, the double-sided membrane demonstrated a lower diffusion rateof salt form the brine into the feed of the experiment, as shown in FIG.16.

Embodiments of the present invention comprise surface functionalizationchemistry of the final material. Surfactants can be cationic, anionic,or zwitterionic. For reverse osmosis, this presents a challenge forsalts since according to DLVO theory salt in solution will form a doublelayer at the membrane surface. The opposite is true for a hydrophobicsurface in solution. There will be a decreased density of water at thesurface resulting in a decreased density of dissolved ions. Surfacefunctionalization chemistry can render surfaces hydrophilic orhydrophobic depending on the application (e.g. forward osmosis versusreverse osmosis).

In one embodiment of the present invention, the surface of the materialis methylated with (CH₃ CH₂O)(CH₃)₃Si to render the materialhydrophobic. The result is a hydrophobic membrane with sub nanometerporosity for the extraction of low surface tension liquids, e.g. alkanesand alcohols, from water. In FIG. 17, several 10 μl drops were placed ona UV Clean 20 wt % DLPC on 0.1 micron PES membrane (left sample) and aUV Clean 20 wt % DLPC on 0.1 micron PES membrane which after assemblyand curing was surface functionalized with a methylated silane(specifically, 600 microliters of 10 wt % ethoxy(trimethyl)silane)(right sample). The resulting material is more hydrophobic than theoriginal material, as shown by the water drop spreading less on thetreated hydrophobic membrane surface than on the untreated hydrophilicmembrane surface.

Self assembled thin films on porous supports can be used in manyconfigurations for separations. FIG. 18 illustrates one embodiment of aflat sheet membrane cartridge configuration. In this configuration waterflows perpendicular to the surface of the membrane. Water passingthrough the membrane (the permeate) has a lower concentration of solutesthan the retentate (water remaining in the cartridge). (A) denotes theflow of the retentate and (B) denotes the flow of the permeate. (C) and(G) are a fitting or a combination of fittings holding the biomimeticsurfactant nanostructure in place. (D) is an optional porous materialsupporting and/or structuring the biomimetic surfactant nanostructure.In some embodiments, this layer comprises metal washer, which is ofparticular importance in applications requiring the membrane to bebackflushed and/or to prevent membrane leaking. (E) denotes thebiomimetic surfactant nanostructure and (F) is an optional porousmaterial to increase the mechanical stability of the biomimeticsurfactant nanostructure. (H) is an optional outlet enabling flow ordraining of rejected solution. All data presented in the Examples forthis configuration were measured using a flat sheet membrane cartridgewithout a drain and/or rejection flow.

FIGS. 19 and 20 illustrate embodiments of the invention used in spiralwound membrane cartridges. In this configuration, water flow istangential to the membrane surface. For concentration applications (FIG.19), solution can pass directly through the core on which the membraneis wound. The retentate (the solution within the core) is enriched as ittravels down the core and water selectively permeates tangentiallythrough the spiral wrapped membrane. (A) denotes the flow of theretentate. (B) is the spiral membrane cartridge. (C) is the flow of thewater being removed from the solution and (D) is the flow of theconcentrate. (E) is a hollow core that is porous allowing for tangentialflow. (F) denotes a membrane spiral comprising one or more layers. Theselayers may comprise a single piece or multiple pieces. Each layer can beidentical or different. It is preferable to dispose a large pore meshbetween the biomimetic surfactant nanostructure layers to distribute thepressure evenly across the biomimetic surfactant nanostructure surface.(G) is the direction of the flow of the removed water. For waterpurification and concentration applications (FIG. 20), the corepreferably comprises a stop to prevent direct flow of feed solution. (A)denotes the flow of the retentate. (B) is a flow stop. (C) is the flowof the water being purified. (D) and (I) denote a solid layer to preventthe loss of water from the cartridge. (E) is the flow of rejectedsolution and (F) is the flow of purified water. (G) is a hollow corethat allows for tangential water flow with a direct flow stop. Thehollow core preferably comprises a pore size greater than 0.03 microns.(H) denotes the membrane spiral, which preferably comprises multiplelayers. These layers may comprise a single piece or multiple pieces.Each layer can be identical or distinct. It is preferable to dispose alarge pore mesh between the biomimetic surfactant nanostructure layersto distribute the pressure evenly across the biomimetic surfactantnanostructure surface. Water must flow through the membrane, and returninto the core behind the stop, to be collected in the permeate. Rejectedwater falls out of the side.

Other configurations than those presented including configurations withdiffering material orientation, flow direction, additional depositionsof chemical, insertion of one or more electrodes, and/or additions ofthin films may be preferable on an application specific basis. Forexample, to use of the biomimetic surfactant nanostructure for ionexchange applications or in a fuel cell, inserting electrodes on eitherside of the biomimetic surfactant nanostructure is typically required.

Hollow membrane fibers may be used to filter water. The fibers enablegreater permeability per element volume because the fibers have moresurface area than the spiral wound elements. The ability of embodimentsof the present invention to perform separations using surfactantmesophases, and the ability to form surfactant self assembling thinfilms on porous supports, enable the assembly of surfactant selfassembling thin films on the inside and the outside of a hollow fiber.To coat a hollow fiber membrane on the inside, the H2O2 Boil TEOSprotocol is preferably used to prepare the surface. Millipore water ispreferably used to flush and pre-wet the fiber for interfacial assembly.Self assembly solution is then flushed through the inside of the fiberand preferably allowed to polymerize overnight. The ends of the fibermay optionally be blocked to prevent leaking of self assembly solution.To coat the outside of a fiber, the fiber preferably undergoes the sameH2O2 Boil TEOS protocol. Then the fiber is flushed preferably coatedwith water. The outside of the fiber is then preferably coated with selfassembly solution. One method to coat the outside of the fiber is topull it through a circular orifice which contains self assemblysolution. The self assembly solution is preferably allowed to polymerizeovernight.

Certain methods in accordance with embodiments of the present inventionstabilize the resulting thin film, allowing it better withstandmechanical deformation (tension and/or compression). Both mathematicalmodels of lipid bilayer transport and experimental results confirm thatsolute permeability across a lipid bilayer decreases with increases inmembrane thickness. For example, the negative correlation between lipidchain length and bilayer permeability has been experimentally measured.There are many ways to change membrane thickness including, but notlimited to, lipid molecular structure (e.g. tail length, lipid class),mechanical tension, chemical swelling, chemical association, and/orlipid interdigitation. The same is true for stabilized surfactantmesostructure thin films. The effect of tension induced by normalsurface pressure on a biomimetic surfactant nanostructure isdemonstrated in FIGS. 21A and 21B. The effect of pressure on rejectionpercentage. FIG. 21A is data for single free standing biomimeticsurfactant nanostructure assembled from a 5 wt % lipid solutioncomprising 10:1 DLPC to Gramicidin between two PES membranes preparedusing the UV clean. FIG. 21B is data for a single free standingbiomimetic surfactant nanostructure assembled from a 10 wt % lipidsolution comprising 10:1 DLPC to Gramicidin between two PES membranesprepared using the UV clean. The rejection of methanol throughbiomimetic surfactant nanostructures decreases with pressure because ofthe lateral tension induced by the solvent flow through the membrane. Byinserting a mechanical backing, for example a porous mesh (˜0.1 mm poresmanufactured by DelStar, El Cajon, Calif.) on a metal mesh (˜5 mm pores)disposed behind a single free standing biomimetic surfactantnanostructure (which was assembled from a 10 lipid wt % solution contain10:1 DLPC to Gramicidin between two PES membranes prepared using UVclean with a methanol concentration of 20% w/w), the rejection ofmethanol reached steady state operation after approximately 40 minutes,as shown in FIG. 22A. Furthermore, the flux of solution through themembrane slowed as a function of time, as shown in FIG. 22B, suggestingthe ability to concentrate methanol within the retentate.

Particular embodiments of this invention provide for the concentrationof solutes via the membrane. Molecules, ions, and particles that arerejected by the membrane can be concentrated within the solute. Oneexample method comprises configuring the membrane in a tangential flowapparatus. Particular embodiments of this invention can be used toconcentrate methanol. As shown in FIG. 23, a volume (5.5 ml) of 20% w%/w % methanol solution (25 ml) was pumped through a single freestanding biomimetic surfactant nanostructure, assembled from a 10 lipidwt % solution contain 10:1 DLPC to Gramicidin between two PES membranesprepared using UV clean. The membrane was backed with a millimeter sizedporous mesh backed by a porous metal scaffold. A one inch metal washerwas glued to the other side of the membrane with Devcon 5 minute epoxy.Flow rate was 0.074 ml/min and the average pressure was 11.4 PSI. Themembrane area was 1.13 cm². The membrane was orthogonal to solution flowin a homemade membrane cartridge. The sides of the membrane were gluedto prevent leaking. The concentration of methanol in the retainedsolution increased by 5.3%, as expected from a mass balance given theinitial methanol concentration of the feed solution and the measuredmethanol concentration of the permeate solution.

Certain embodiments of this invention provide for the formation ofbiomimetic surfactant nanostructures using various types of porousmaterials. The rational design and integration of specific membranesupports for enhanced material stability is critical for separations ofspecific solutes because of the limitation of supporting materialsincluding, but not limited to, chemical stability in solutes, mechanicalstability in solutes, pore size, pore shape, cost, separationefficiency, and system compatibility. One limitation of separatingsolvents like alcohols, ketones, acetone, or benzene is the chemicalstability of the supporting membranes. For example, PES dissolves inmany organic solvents, including acetone, and is mechanically unstablein alcohols. The mechanical stability of PES, HI-PTFE (hydrophilic), andHO-PTFE (hydrophobic) differs in alcohol. Here, the mechanical stabilityof the membrane is defined as the expansion of the material in mixturesof alcohol. FIG. 24A shows the expansion of a 5 cm×1 cm piece of PES asa function of alcohol type and alcohol concentration. FIG. 24B shows theexpansion of 5 cm×1 cm pieces of HI-PTFE and HO-PTFE membranes as afunction of PTFE membrane type, alcohol type and alcohol concentration.Normalized to water, PES expands 6% in pure ethanol and pure butanol.Normalized to water, both HI-PTFE and HO-PTFE do not expand in pureethanol and pure butanol. This makes both HI-PTFE and HO-PTFE ideal foruse with small organic solvents. Expansion of the support induces alateral tension on the biomimetic surfactant nanostructure, whichreduces its performance.

FIGS. 25A and 25B compare two particular embodiments of the inventionseparating 25 ml of 10 w %/w % aqueous ethanol solution from water. Asingle free standing biomimetic surfactant nanostructure was assembledfrom a 10 lipid wt % solution contain 10:1 DLPC to Gramicidin betweentwo HI-PTFE membranes prepared using UV clean. The membrane was backedby both a millimeter sized porous mesh and a porous metal scaffold. Asshown in FIG. 25B, this configuration demonstrates a 17.5% increase inrejection percentage at comparable pressure versus a single freestanding biomimetic surfactant nanostructure was assembled from a 10lipid wt % solution contain 10:1 DLPC to Gramicidin between two PESmembranes prepared using the UV preparation method (FIG. 25A). Bothembodiments had a mechanical backing of porous sheet metal to stabilizethe membrane.

In certain embodiments of this invention, ethanol can be concentrated.In FIG. 26 the results of an ethanol concentration experiment arelisted. A volume (7.4 ml) of 20.5% w %/w % ethanol solution (25 ml) waspumped through a single free standing biomimetic surfactantnanostructure, which was assembled from a 10 lipid wt % solution contain10:1 DLPC to Gramicidin between two HI-PTFE support membranes preparedusing UV clean. The membrane was backed by a millimeter sized porousmesh further backed by a porous metal scaffold. A one inch metal washerwas glued to the other side of the membrane with Devcon 5 minute epoxy.The membrane area was 1.13 cm². Flow rate was 1.2×10⁻⁵ m³/m²/sec with apressure of 5 PSI. The pressure normalized flow rate was 3.48×10⁻¹⁰m³/m²/sec/Pa. The loss was 0.1 ml. The membrane was orthogonal tosolution flow in a homemade membrane cartridge. The sides of themembrane were glued to prevent leaking. The ethanol concentration of theretentate increased by 2.4% over the initial ethanol concentration asexpected from the mass balance given the measured ethanol concentrationof the permeate.

In certain embodiments of this invention, aqueous NaCl can be separatedfrom water, as shown in FIG. 27. The material was 10 wt % Soy PC (95%)from Avanti Polar Lipids (Alabaster, Ala.) in standard silica solutionassembled between two UV cleaned PES membranes (0.030 micron pores). Thevolume of the NaCl solution was 233 ml with a conductivity of 15.4mS/cm. Conductivity was measured using a Horiba B-173 conductivitymeter. The membrane was backed by both a millimeter sized porous meshand a porous metal scaffold. The area of the membrane was 1.13 cm². Thepressure was 5 psi.

In certain embodiments of this invention, aqueous MgSO₄ can beseparated, as shown in FIG. 28. The membrane was 30 wt % Soy PC (95%)from Avanti Polar Lipids (Alabaster, Ala.) in stock silica solutionassembled between two UV cleaned PES membranes (0.030 micron pores). Thevolume of the MgSO₄ solution was 13.2 ml with an initial conductivity of9.0 mS/cm. The final conductivity was 9.2 mS/cm. Conductivity wasmeasured using a Horiba B-173 conductivity meter. The membrane wasbacked by both a millimeter sized porous mesh and a porous metalscaffold. The area of the membrane was 1.13 cm². The pressure was 5 psi.

Multilayer Membranes

Embodiments of the present invention comprise multilayered membranes.Multilayer membranes preferably alternate lamellar layers of selfassembled material and support material. In one exemplary embodiment isillustrated in FIG. 29. Two solid surfaces (A) sandwiched alternatinglayers of porous material (B) and surfactant templated sol-gel selfassembly solution (C). Specifically, HI-PTFE membranes were prepared viaH2O2 Boil TEOS and rinsed in 18.2 MO water. After HI-PTFE membranepreparation, alternating layers of membrane and 400 microliters of BSNSsolution were constructed on a solid surface with the first final layersbeing H2O2 Boil TEOS HI-PTFE membranes. The three stack membrane wassandwiched by another solid surface, dried at room temperature for morethan one hour, and then dried at 80° C. for more than three hours. Theresulting membrane was glued to a mechanical backing. The confinementsimultaneously drives assembly and integrates the resultant film withthe physical confining assembly.

In an example of a multilayered membrane, a three BSNS layer freestanding biomimetic surfactant nanostructure was assembled using 10lipid wt % solution containing 10:1 DLPC to Gramicidin. The porousmaterial was four HI-PTFE membranes prepared using the UV preparationmethod (H2O2 Boil TEOS and rinsed in 18.2 MΩ water). After preparation,alternating layers of H2O2 Boil TEOS HI-PTFE membrane and BSNS solutionwere placed on a solid surface with the final layers being H2O2 BoilTEOS HI-PTFE membranes. The stack of membranes was sandwiched by anothersolid surface, dried at room temperature for more than one hour, andthen dried at 80° C. for more than three hours. The resulting membranewas glued to a mechanical backing. The area of the membrane was 6.16cm². A separation of 10% w %/w % ethanol solution was performed at 2.5PSI. The multilayered membrane rejected ethanol at an average of 80.5%,as shown in FIG. 30A, and demonstrated nearly constant water flux formore than 200 minutes, as shown in FIG. 30B.

The physical properties of embodiments of multilayered membranes can befundamentally and non-trivially different than multiple single membranesstacked in series. The separation of a multi-layered material showsimproved performance over a single layer membrane material and acalculation of the performance of three single layer membranes inseries. Below is a table comparing the rejection and the flux of asingle layer (Single Layer), three single layers in series (Three SingleLayers), and a triple multilayer (Triple Multilayer). For thecalculation of the Three Single Layer, the pressure was calculated bymultiplying the pressure for one layer by the number of layers, the fluxwas calculated by dividing the flux for one layer by the number oflayers, and the rejection percentage was calculated by raising one minusthe rejection percentage to the number of layers then subtracting thatnumber from one. The pressure, flux and rejection of the multilayeredmembrane are better than projected for membranes in series. This may beattributed to the differences in assembly conditions between the singlelayer (where each porous material has a solid surface on one side) andthe multilayer (where all but two porous materials do not have a solidsurface on either side).

TABLE 4 Number Ethanol of Flux Rejection Layers Pressure (m{circumflexover ( )}3/m{circumflex over ( )}2/sec/Pa) (%) Single Layer 1 .5 1.50 ×10⁻¹⁰ 22% Three Single 3 2.5 5.00 × 10⁻¹¹ 53% Layers Triple Multi- 3 52.33 × 10⁻¹¹ 80% layer

In one embodiment of a multilayer membrane, a four biomimetic layermembrane was assembled using 10 lipid wt % solution containing 10:1 DLPCto Gramicidin. The porous material was five HI-PTFE membranes preparedusing the UV preparation method (H2O2 Boil TEOS and rinsed in 18.2 MΩwater). After preparation, alternating layers of H2O2 Boil TEOS HI-PTFEmembrane and BSNS solution were placed on a piece of Teflon with thefinal layers being H₂O₂ Boil TEOS HI-PTFE membranes. The stack ofmembranes was sandwiched by another solid surface, dried at roomtemperature for more than one hour, and then dried at 80° C. for morethan three hours. After drying, the resulting membrane was glued to amechanical backing. The sample area was 6.15 cm². A separation of 5% w%/w % butanol solution was performed at 25 PSI and 10 PSI. Flux andrejection data is shown in FIG. 31. The lines with diamonds refer to theaxis on the left (flux). The lines with squares refer to the axis on theright (Rejection Percentage).

Electrochemical and Related Applications

TABLE 5 compares the selectivity of a Nafion membrane versus acalculation for a free standing BSNS comprising 10 mol % gramicidin, atransporter. The values listed for Nafion are from the literature. Thevalues listed for the BSNS are based on calculations parameterized byexperimental measurements. The proton and methanol conductivity of eachlipid bilayer was modeled using parameters from single channelgramicidin conductivity measurements and giant unilamellar vesicle(‘GUV’) experiments respectively. Proton conductivity was determined tobe 602.6 S per cm² and methanol permeability was determined to be1.2×10⁻⁵ cm/sec per bilayer. The BSNS equivalent circuit was theequivalent circuit of 100 lipid bilayers in parallel, roughly a onemicron thick material. Proton conductivity and methanol permeabilitywere divided by the total number of layers in accordance with theequivalent circuit model of a lipid bilayer. As such, these valuesrepresent an estimate of the performance of a direct methanol fuel cell(DMFC) constructed using this BSNS. Membrane crossover in a typical DMFCrequires dilution of methanol to 3 M-4 M at the anode and reduces fuelcell power density (W cm⁻²) by roughly 50%. However, for the BSNSdescribed above, we predict a 1733× decrease in methanol permeabilityand a 5.93×10⁻⁸ decrease in polyvalent cation permeability versusNafion. The resulting DMFC would be approximately 50% more efficient andcould operate on ‘neat’ methanol.

TABLE 5 Predicted Ratio BSNS Nafion 117 BSNS to Nafion Thickness ~100 μm~1 μm .001 Conductivity 7.5 S/cm² 6.026 S/cm² .803 (S) (Lee W et al)Methanol 2.08 × 10⁻⁴ cm/sec 1.2 × 10⁻⁷ cm/sec  5.7 × 10⁻³ Permeability(Lee W et al) (P) Polyvalent 5.93 × 10⁻⁸ cm²/sec >10⁻¹⁶ cm²/sec 1.69 ×10⁻⁷ Cation (Xia J et al) Permeability

Biomimetic surfactant nanostructures, some comprising Gramicidin, wereself assembled between two Nafion membranes as described in FIGS. 8A, 8Band 8C. The BSNS self assembly solution comprised lipids (Lipid 5, Lipid1, Lipid 2, 5 wt % DLPC, 10 wt % DMPC), comprised lipids and gramicidin(Gram 4, 10 wt % 10 DMPC: 1 Gram), or comprised neither lipids norgramicidin (Silica, Silica 1, Silica 2). Transporter materials werecharacterized by through plane conductivity measurements. Through planeconductivity was measure by sandwiching the membrane between two steelplates ˜1 cm² and measuring the resistance with an ohm meter. Membranesand steel plates were stored in specific concentrations of acid for atleast 2 minutes before measurement. FIGS. 32A-32C compare theconductivity of a control and three free standing BSNS hierarchicalmembranes with and without a transporter. In FIG. 32A, the through planeresistance of the three types of membranes: Silica (lipid free), Lipid 5(transporter Free), and Gram 4 (transporter including) were compared atvarious concentrations of sulfuric acid. We measured a 6.375× increasein resistance for the transporter-free BSNS membrane (Lipid 5) versusthe transporter-including BSNS membrane Gram 4. As expected fromexperiments with vesicles in solution, this result demonstrates that theinclusion of the transporter Gramicidin in the BSNS increases theconductivity of the biomimetic surfactant nanostructure. Furthermore,the resistance of the control membrane (silica) was comparable to thetransporter containing BSNS (Gram 4) at 1 M sulfuric acid. Thereforeresistance was membrane-limited, not transporter-limited. When comparedto TABLE 5, this suggests that the thickness of the BSNS layer is lessthan 1 micron.

Stability of these materials in acidic and high concentration alcohol isimportant for fuel cell applications. The conductivity of the membraneswas maintained over approximately one day despite storing the samples ineither pure (neat) methanol (FIG. 32B) or 1 M H2504 (FIG. 32C). As shownin FIG. 32B, after day 1, there is a dramatic increase in resistance,suggesting material failure. In FIG. 32C, two surfactant free materials(Silica 1, Silica 2) and one surfactant containing material (5 wt %DLPC) were stored in 1 M sulfuric acid. After three days, the resistanceof the surfactant containing material has not significantly changed.This suggests that the material has remained assembled despite thecorrosive environment. This stability suggests that materials accordingto this embodiment may be useful for electrolysis, separations and fuelcell applications.

For direct methanol fuel cells and molecular separations, a reduction inthe permeability of methanol through a membrane is important. Thisembodiment, a free standing BSNS, has a 4× decrease in methanolpermeability compared to Nafion. Methanol permeability was measured byseparating methanol with a either a Nafion 117 or a free standing BSNS,in equal volumes of 18.2 MΩ Millipore water and a high concentrationaqueous (18-23 Brix) methanol solution. The methanol concentration ofthe initially pure water was measured as a function of time using aAtago 4436 PAL-36S Digital Pocket Methyl Alcohol Refractometer. Thepermeability coefficient relates the flux to the concentration gradientusing the following equation

$J = {{\frac{d}{dt}\Delta \; C*\frac{V}{A}} = {P\; \Delta \; C}}$

where J is the flux (cm² sec⁻¹), P is the permeability (cm/sec), ΔC isthe concentration gradient (Brix), V is the volume of one side, and A isthe interfacial area. The ratio of volume to area for the permeabilitycell was 0.3 cm. The concentration gradient (ΔC) versus time (as shownin FIG. 32D) was fit to a single exponential with a rate coefficient k.The permeability was calculated using

$P = {k\frac{V}{A}}$

where P is the permeability (cm/sec), V is the volume of one side (cm³),A is the interfacial area (cm²), and k (sec⁻¹) is the rate constant fromthe fit. The methanol permeability was measured for three Nafion 117membranes, a biomimetic nanostructured membrane not comprising atransporter, and a biomimetic nanostructured membrane comprising atransporter. For the Nafion 117 membranes, the average methanolpermeability coefficient over three experiments was 1.2×10⁴ cm sec⁻¹.This is in close agreement with the Nafion 117 methanol permeabilityvalue in TABLE 5. For the sample embodiments of the invention, theaverage methanol permeability was 0.3×10⁻⁵ cm sec⁻¹. Despite theinclusion of the transporter in the BSNS (10 wt % 10 DMPC: 1 Gram), thepermeability coefficient was the same as the transporter-free BSNS (10wt % DMPC). As expected from experiments with vesicles in solution, thisresult demonstrates that the inclusion of Gramicidin in the BSNS doesnot increase the methanol permeability of the biomimetic surfactantnanostructure. Thus the lipid structure is preserved despite theinclusion of the transporter. The methanol permeability was reduced by afactor of four for the invention versus Nafion 117.

Embodiments of the present invention may be used as an electrolyte,membrane electrode assembly, or electrochemical cell forelectrochemistry; one configuration is illustrated in FIG. 33. The highconductivity and low crossover of biomimetic surfactant nanostructuresmake them desirable as electrolytes for liquid fed fuel cells andbatteries. Biomimetic surfactant nanostructure 3330 is disposed betweengasket layers 3320 and anode flow plate 3310 and cathode flow plate3340. Either or both of the flow plates optionally comprise a serpentinegraphite plate. The plates may be different. The integration of a BSNScontaining passive transporters, or alternatively a stabilizedsurfactant mesostructure, with one or more Nafion membranes to create afree standing membrane preferably comprises greater selectivity thancurrent industrial membranes. This has an important application for bothfuel cells and batteries where membrane “crossover” of fuel orelectrolyte reduces efficiency and energy storage capacity. Biomimeticsurfactant nanostructure 3330 may optionally comprise a multiscale selfassembled membrane electrode assembly (MEA), which may optionallycomprise one or more of the following: the catalyst, the membrane, thegas diffusion layer (GDL), and/or a carbon paper. The sandwiched portionof the MEA is the surfactant templated nanostructure produced usingphysical confinement. The membrane may be supported by any solid surfaceor GDL on a solid surface. A complete membrane electrode assembly (MEA)comprising a catalytic layer on the GDLs may be produced in a similarmethod. Alternatively, this device could comprise an electrolyte for abattery if a conductive ion exchange membrane is substituted for theGDL.

Similarly, redox flow batteries, such as vanadium ion redox batteries(VRB), have reduced efficiency due to membrane crossover of aqueousredox ions. The elimination of crossover in redox flow batteries byusing the above BSNS would enable a battery with an efficiency >90%,similar to lithium ion batteries, which do not suffer from electrolytecrossover.

A similar configuration could be used for separations such as urearemoval, dialysis, desalinization, distillation, alcohol purificationand the chloro-alkali process.

Materials made in accordance with embodiments of the present methods maybe suitable for use: as a membrane in a membrane electrode assembly fordirect methanol fuel cells, as a membrane electrode assembly for fuelcells, as a membrane in a membrane electrode assembly used for biofuelcells, as a membrane in a membrane electrode assembly used for anelectrochemical cell, in active devices and smart devices via synergiesof channels, in chloro-alkali cells, in electrochemistry, in chemicalmanufacture, and/or in enzymatic conversion of molecules.

Single-Chain Surfactants

Assembly of a mesostructured sol gel thin film comprising single chainsurfactants on a porous material changes its hydrophilicity, its surfacecharge and its filtration properties. Assembly can be via any roll toroll coating methods including dip, reverse roll, gravure, knife, slotdie, silk screen or other comparable coating techniques. Mesostructuredsol gel materials include surfactant mesophases encapsulated orstabilized using sol gel chemistry. Mesophases may comprise single chainsurfactants with one or more chain lengths of surfactant. Surfactantscan be cationic, anionic, zwitterionic, non-ionic or a combination thereof. Surfactant mesophases may be lamellar, micellular, hexangonal,cylindrical, random, or a combination there of. One method to create asurfactant mesophases is to coat a porous material with a mixture ofalcohol, water, surfactant, and sol-gel precursor. The resulting thinfilm can be annealed via the addition of alcohol after coating. In anembodiment of this method, thin films are cured for >48 hrs at >40Celsius. The ratio of surfactant to sol-gel precursor determines thefinal structure of the mesophase. Porous materials include plastics,ceramics and metals. Other porous materials include microfiltrationmembranes, ultrafiltration membranes, and nanofiltration membranes. Poresizes of relevant porous materials can be classified by poly ethyleneglycol (PEG) exclusion, by average pore diameter, or by both. Theminimum size of PEG in solution which is the retained by the porousmaterial during filtration is known as the molecular weight cutoff(MWCO). Relevant pore sizes are preferably between approximately 0.001microns and 0.3 microns. Relevant molecular weight cutoffs for porousmaterials are preferably between approximately 100 g/mol and 500,000g/mol.

Due to the more energetically favorable interaction, a water dropletwill spread over a larger area on a surface with increasedhydrophilicity. Water droplets are on the order of 10 microliters. Forsolid materials, the hydrophilicity can be quantitatively measured usingthe contact angle of the droplet. Solid silica surfaces are known tohave a contact angle which approaches zero, indicating complete wetting.Solid plastic surfaces used for filtration are known to have contactangles between 40 and 50 degrees. For porous materials, water will wetthe material preventing contact angle measurements. Instead,hydrophilicity of porous materials can be qualitatively compared via thespreading area of a water drop where the area of the water drop will begreater for the more hydrophilic material. Increased hydrophilicity of aporous material used for filtration is desirable for increasing flux andreducing fouling.

FIG. 38 shows the relative spreading of a water droplet on materialswith and without a mesostructured sol gel film. The top left material(Polysulfone) is a polysulfone ultrafiltration membrane with a 100,000Dalton molecular weight cutoff (MWCO). It is a control without themesostructured film. The bottom left material (0.03 um PES) is amicrofiltration membrane with an average pore diameter of 0.03 microns.It is a control without a mesostructured film. The top right material(0.1 um PES) is a microfiltration membrane with an average pore diameterof 0.1 microns. It is a control without a mesostructured film. Thebottom right material (zNano C1) is a mesostructured sol gel thin filmcoated on a microfiltration membrane with an average pore diameter of0.03 microns. The mesostructured thin film was created from a selfassembly solution. The self assembly solution was prepared by addingcetyl trimethyl ammonium bromide (CTAB), a cationic single chainsurfactant, to 0.48:0.48:0.04 volumetric parts oftetraethylorthosilicate, ethanol and water. The amount of CTAB addedresulted in a final concentration of eight weight percent. The selfassembly solution was sonicated using a Branson 1500 sonicator for 90minutes at 40 Celsius. The support membrane is then rinsed in water,oxidized then coated with the self assembly solution. The resulting thinfilm can be annealed via the addition of alcohol after coating. Usingthis method, thin films are cured for >48 hrs at >40 Celsius. In themiddle of the image is a ruler to provide a scale bar for the image. Tomeasure hydrophilicity, 10 microliters of water purified using reverseosmosis was placed on each material. The diameter of each water drop(clockwise from top left) was 0.298 cm, 0.923 cm, 1.726 cm, and 0.893cm. The material with the mesoporous sol gel film had increasedwettability in comparison to the Polysulfone, the PES 0.03 um and thePES 0.1 um materials. As the pore size of the non-mesostructured controlmaterials increased, the spreading of water increased despite thecomparable hydrophilicity of polysulfone (Polysulfone) andpolyethersulfone (PES 0.03 um and PES 0.1 um). The mesostructuredmaterial does not conform to this trend. Despite the smaller pore size(0.03 um pore), the material with the mesostructured sol gel films hadcomparable or superior hydrophilicity to the PES 0.1 um membrane (0.1 umpore).

FIG. 39 shows the relative spreading of a water droplet on materialswith and without a mesostructured sol gel film. The top left material(10 k MWCO PS) is a polysulfone ultrafiltration membrane with a 10,000Dalton molecular weight cutoff (MWCO). It is a control without themesostructured film. The bottom left material (zNano CA1) is amesostructured sol gel thin film on an ultrafiltration membraneresulting in a material with a MWCO of 35,000 Daltons. Themesostructured thin film was created from a self assembly solution. Theself assembly solution was prepared by adding cetyl trimethyl ammoniumbromide (CTAB) to 0.48:0.48:0.04 volumetric parts oftetraethylorthosilicate, ethanol and water. The amount of CTAB addedresulted in a final concentration of eight weight percent. The selfassembly solution was sonicated using a Branson 1500 sonicator for 90minutes at 40 Celsius. 1. Support membrane is then rinsed in water,oxidized then coated with the self assembly solution. The resulting thinfilm can be annealed via the addition of alcohol after coating. Usingthis method, thin films are cured for >48 hrs at >40 Celsius. The topright material (zNano CA2) is a mesostructured sol gel thin film on anultrafiltration membrane resulting in a material with a MWCO of 35,000Daltons. The mesostructured thin film was created from a self assemblysolution. The self assembly solution was prepared by adding cetyltrimethyl ammonium bromide (CTAB) to 0.32:0.64:0.04 volumetric parts oftetraethylorthosilicate, ethanol and water. The amount of CTAB addedresulted in a final concentration of eight weight percent. The selfassembly solution was sonicated using a Branson 1500 sonicator for 90minutes at 40 Celsius. Support membrane is then rinsed in water,oxidized then coated with the self assembly solution. The resulting thinfilm can be annealed via the addition of alcohol after coating. Usingthis method, thin films are cured for >48 hrs at >40 Celsius. CTAB is acationic single chain surfactant. The bottom right material (0.03 umPES) is a microfiltration membrane with an average pore diameter of 0.03microns. It is a control without a mesostructured film. At the bottom ofthe image is a ruler to provide a scale bar for the image.

To measure hydrophilicity, 10 microliters of water purified usingreverse osmosis was placed on each material. An image of the result isprovided in FIG. 39. The diameter of each water drop (clockwise from topleft) was 0.267 cm, 1.03 cm, 0.76 cm, and 0.73 cm. The materials withthe mesoporous sol gel films had increased wettability in comparison toboth the 10 k MWCO PS and the 0.03 um PES material. As the pore size ofthe non-mesostructured control materials increased, the spreading ofwater increased despite the comparable hydrophilicity of polysulfone (10k MWCO PS) and polyethersulfone (0.03 um PES). The mesostructuredmaterial does not conform to this trend. The materials with themesostructured sol gel films had comparable or superior hydrophilicityto the 0.03 um PES membrane despite their smaller pore size (35,000daltons MWCO).

Mesostructured sol gel thin films comprising single chain surfactants ona porous material improve the porous material's function as a filterrelative to the uncoated porous material. The classes of solutions wherefiltration is improved are solutions containing surfactants andemulsions. Plausibly, this is because the mesostructured has improvedhydrophilicity and is composed of a large fraction of surfactants.Emulsions are defined as solutions comprising at least water,surfactants and organic molecules. There can be one or more moieties ofsurfactants. There can be one or more moieties of organics.

FIG. 40 demonstrates the improved filtration properties of a porousmaterial with and without a mesostructured sol gel film for a solutioncontaining surfactants. The solution filtered was 100 ppm NaCl, 50 ppmCaCl, and between 250 ppm and 1000 ppm sodium dodecyl benzene sulfonate(SDBS). The pH of the solution was adjusted to 9 using NaOH. Afterpreparation, the solution, Bulk was filter by three 1″×3″ materials,Control, CA2, CA1, in parallel using a homemade crossflow filtrationcell in a dead end mode, meaning 100% water recovery. Materials filteredthe Bulk solution for at least 10 minutes before beginning theexperiment. The pressure was 5.5 PSI. All turbidity and permeabilitydata is after one hour of filtration. All optical absorptionmeasurements are after 40 minutes of filtration.

FIG. 40 compares the surfactant concentration of four samples (Bulk,Control, CA 1, and CA 2) are compared in the graph on top of Slide 3.Bulk is the solution filtered. Control is a polyethersulfone (PES)membrane with an average pore size of 0.1 microns. CA1 is amesostructured sol gel thin film on a microfiltration membrane with anaverage pore size of 0.1 microns. The mesostructured thin film wascreated from a self assembly solution. The self assembly solution wasprepared by adding cetyl trimethyl ammonium bromide (CTAB) to0.48:0.48:0.04 volumetric parts of tetraethylorthosilicate, ethanol andwater. The amount of CTAB added resulted in a final concentration ofeight weight percent. The self assembly solution was sonicated using aBranson 1500 sonicator for 90 minutes at 40 Celsius. Support membrane isthen rinsed in water, oxidized then coated with the self assemblysolution. The resulting thin film can be annealed via the addition ofalcohol after coating. Using this method, thin films are cured for >48hrs at >40 Celsius. CA2 is a mesostructured sol gel thin film on amicrofiltration membrane with an average pore size of 0.1 microns. Themesostructured thin film was created from a self assembly solution. Theself assembly solution was prepared by adding cetyl trimethyl ammoniumbromide (CTAB) to 0.32:0.64:0.04 volumetric parts oftetraethylorthosilicate, ethanol and water. The amount of CTAB addedresulted in a final concentration of eight weight percent. The selfassembly solution was sonicated using a Branson 1500 sonicator for 90minutes at 40 Celsius. Support membrane is then rinsed in water,oxidized then coated with the self assembly solution. The resulting thinfilm can be annealed via the addition of alcohol after coating. Usingthis method, thin films are cured for >48 hrs at >40 Celsius. CTAB is acationic single chain surfactant.

The top of FIG. 40 is a double y-axis column graph which compares theremoval of surfactants by a porous material with and without amesostructured sol gel film as a function of surfactant concentration.The values corresponding to the left side y-axis are the columns and area measure of the concentration of surfactants as measured by the opticalabsorption of the benzene ring. The values corresponding to the righty-axis are the lines and are the rejection of surfactant calculatedusing the equation below:

${Rejection} = \frac{C_{bulk} - C_{permeate}}{C_{bulk}}$

Below the graph is a table with five columns. The first column(Experiment) lists the concentration of the solutes and the pH of thefeed water. The second column (‘SDBS ppm’) lists the concentration ofthe SDBS in the feed water. The third column (‘SDBS NTU’) lists theturbidity of the feedwater. The final two columns are the filtrationproperties of the materials: permeability (permeability), measured ingallons per square feet of membrane per day and turbidity (NTU), measurein Nephelometric Turbidity Units (NTU).

The graph in FIG. 40 demonstrates the improved rejection of the porousmaterial with a mesostructured sol gel film. With 250 ppm to 500 ppm ofsurfactant, the rejection of surfactant of the porous material with andwithout a mesostructured sol gel film is less than 10%. With 1000 ppm ofsurfactant, the rejection of the surfactant by each material is greaterthan 40%. The rejection of the surfactant by the CA2 material is 15%greater than the Control material. At 1,000 ppm, SDBS is at aconcentration greater than its critical micelle concentration, known tobe approximately 418 ppm. The result is larger average particle sizeenabling rejection by the materials. The increase in rejection by theCA2 material is most likely due to the decrease in the material's poresize.

The table in FIG. 40 demonstrates the improved permeability andrejection of the porous material with a mesostructured sol gel film. Atlow concentrations of surfactant, the permeability of CA1 and CA2 arelower than the Control. This is expected due to the addition of themesostructured material on both porous materials, CA2 and CA1. At 1,000ppm of surfactant, unexpectedly the permeability of both the CA2 and CA1materials were greater than the control. The CA2 material has 34%greater permeability than the control. The CA1 material has 19% greaterpermeability than the control. This is most likely due to the improvedwetting of the materials, CA1 and CA2 in comparison to the Control. Acomparison of turbidity numbers in each column within each row confirmthe results of the measurements conducted by optical absorption. Thereis at most 20% rejection of SDBS at concentrations below 500 ppm. At1,000 ppm of SDBS, the rejection of each material as measured byturbidity is 62%, 69% and 73% for the CA2 material, CA1 material, andControl material. The increase in rejection at 1,000 ppm is consistentwith the optical absorption measurements. The relative rejection betweenthe CA2 material and the Control material is inconsistent since therejection of CA2 is higher in absorption measurements and the rejectionof the Control material is higher in turbidity measurements. Becauseturbidity is a scattering technique, scattering intensity is a functionof both particle size and particle concentration. Therefore, thefiltration of the surfactants through CA2 may produce fewer, smallerparticles. If this is true, the permeate would have higher turbiditydespite lower concentration. Therefore, the optical absorption techniqueis more reliable.

FIG. 41 demonstrates the improved filtration properties of a porousmaterial with and without a mesostructured sol gel film for filtering anemulsion. To produce the emulsion, the following protocol was used.Briefly, a solution of 500 ml of 18.2 MOhm water, containing 200milligrams of sodium chloride, 100 milligrams of calcium chloride andbetween 500 milligrams and 2,000 milligrams of sodium dodecylbenzenesulfonic acid (SDDBSA) was prepared. The solution was mixed for twominutes on a hot plate at room temperature using a stir bar. The pH ofthe solution was adjusted to 9 using sodium hydroxide. An emulsion wascreated via the addition of 1 gram to 6 grams of vegetable oil (‘VeggieOil’). The emulsion was subsequently stirred for one hour on a hot plateat room temperature. Finally, the emulsion was added to 1500 liters ofpH 9 18.2 MOhm water. The resulting solution was circulated with a smallpump to enable mixing. After preparation, the emulsion, Bulk was filterby three 1″×3″ materials, Control, CA2, CA1, in parallel using ahomemade crossflow filtration cell in a dead end mode, meaning 100%water recovery. Materials filtered the Bulk solution for at least 10minutes before beginning the experiment. The pressure was 5.5 PSI. Allturbidity and permeability data is after one hour of filtration. Alloptical absorption measurements are after 40 minutes of filtration.

The graphs in FIG. 41 compare the surfactant concentration of foursamples (Bulk, Control, CA 1, and CA 2). Bulk is the solution filtered.Control is a polyethersulfone (PES) membrane with an average pore sizeof 0.1 microns. CA1 is a mesostructured sol gel thin film on amicrofiltration membrane with an average pore size of 0.1 microns. Themesostructured thin film was created from a self assembly solution. Theself assembly solution was prepared by adding cetyl trimethyl ammoniumbromide (CTAB) to 0.48:0.48:0.04 volumetric parts oftetraethylorthosilicate, ethanol and water. The amount of CTAB addedresulted in a final concentration of eight weight percent. The selfassembly solution was sonicated using a Branson 1500 sonicator for 90minutes at 40 Celsius. Support membrane is then rinsed in water,oxidized then coated with the self assembly solution. The resulting thinfilm can be annealed via the addition of alcohol after coating. Usingthis method, thin films are cured for >48 hrs at >40 Celsius. CA2 is amesostructured sol gel thin film on a microfiltration membrane with anaverage pore size of 0.1 microns. The mesostructured thin film wascreated from a self assembly solution. The self assembly solution wasprepared by adding cetyl trimethyl ammonium bromide (CTAB) to0.32:0.64:0.04 volumetric parts of tetraethylorthosilicate, ethanol andwater. The amount of CTAB added resulted in a final concentration ofeight weight percent. The self assembly solution was sonicated using aBranson 1500 sonicator for 90 minutes at 40 Celsius. Support membrane isthen rinsed in water, oxidized then coated with the self assemblysolution. The resulting thin film can be annealed via the addition ofalcohol after coating. Using this method, thin films are cured for >48hrs at >40 Celsius. The graphs compare the removal of organics by aporous material with and without a mesostructured sol gel film as afunction of oil concentration. The values corresponding to the y-axisare the columns and are a measure of the concentration of Veggie Oil asmeasured by the optical absorption of the benzene ring.

The first column in the table in FIG. 41 (Experiment) lists theconcentration of the solutes and the pH of the feed water. The secondcolumn (‘Veggie Oil PPM’) lists the concentration of the SDBS in thefeed water. The third column (‘Veggie Oil NTU’) lists the turbidity ofthe solution to be filtered (Bulk). The final two columns are thefiltration properties of the materials: permeability (permeability),measured in gallons per square feet of membrane per day and turbidity(NTU), measure in Nephelometric Turbidity Units (NTU).

The graphs in FIG. 41 demonstrate the improved rejection of the porousmaterial with a mesostructured sol gel film. With 500 ppm of Veggie Oil,the rejection of organics is 58.7% by the Control, 48.2% by CA1 and−12.4% by CA2. This demonstrates improved rejection by the Control at500 ppm. With 1000 ppm of Veggie oil, the rejection is 2.6% for theControl, 88.9% for CA1, and 89.4% for CA2. This demonstrates therejection of the porous material with a mesostructured sol gel film whenfiltering highly concentrated emulsions.

The table in FIG. 41 demonstrates the improved permeability andrejection of the porous material with a mesostructured sol gel film. Italso confirms the measurements in the graph above. At 500 ppm of VeggieOil, the permeability of CA1 and CA2 are lower than the Control. This isexpected due to the addition of the mesostructured material on bothporous materials, CA2 and CA1. At 1,000 ppm of Veggie Oil, unexpectedlythe permeability of CA2 is 36% greater than the Control. This isconsistent with the relative increase in permeability, 34%, of CA2 whenfiltering 1,000 ppm SDBS in FIG. 40. The CA1 material has 36% of thepermeability of the control suggesting increased fouling of the surface.A comparison of turbidity numbers in each column within each row confirmmost of the results of the measurements conducted by optical absorption.The permeability of CA2 is 12% greater than the Control at 3,000 ppm ofVeggie Oil. One specific difference is the rejection of turbidity by theCA2 material at a concentration of 500 ppm Veggie Oil is 86.6%. Thissuggests that either the optical absorption measurement or the turbiditymeasurement is incorrect. Because the rejection of the CA2 is greaterthe 80% for 1,000 ppm of Oil by both turbidity and optical absorption,and greater than 80% at 3,000 ppm of Veggie Oil by turbidity, theoptical absorption measurement at 500 ppm was most likely contaminated.In contrast, at both 1,000 and 3,000 ppm of Veggie Oil, the Controlmembrane has zero rejection by turbidity and optical absorptionmeasurements. By eye, the Control permeate is indistinguishable from theBulk at both 1,000 ppm and 3,000 ppm of oil. In comparison at 1,000 ppmof Veggie Oil, the CA2 and the CA1 materials produce 89.4% and 88.9%rejection by optical absorption, 87.7% and 96.0% rejection by turbidityrespectively. In comparison at 3,000 ppm of Veggie Oil, the CA2 and theCA1 materials produce 90.0% and 89.2% rejection by turbidityrespectively. This demonstrates the improved ability of the material tofilter emulsions.

Water from the bilge of a boat (‘Bilge Water’) needs to be treatedbefore it is discharged. Bilge water is composed of particles, oil, andsurfactants. To compare the purification efficiencies of variousmembrane technologies, we created an oil water emulsion using a modifiedversions of Resolution MEPC.107(49) Revised. Briefly, 0.9 g of eithernegatively charged Sodium Dodecylbenzene Sulfonic Acid (SDDBSA) orpositively charged cetyl trimethyl ammonium bromide (CTAB) was mixedwith 178 ml of Tap Water for two minutes on a hot plate at roomtemperature. The emulsion was created via the addition of 9 g of SAE20W-50 Valvoline and was subsequently stirred for one hour on a hotplate at room temperature. Finally, the emulsion was added to Tap Watersuch that the emulsion was 6 wt % of the final solution. For emulsionscontaining 30,000 ppm of NaCl (‘Oil Water Emulsion 03+33 g per L NaCl’),100 g of Instant Ocean (www.instantocean.com) was also added to thefinal solution. The final solution was mixed using a centripetal pumpfor one hour. The concentration of Valvoline was roughly 3,000 ppm inthe final solution. It is important to note that there are zerosuspended solids other than those in the emulsion. A table quantifyingthe turbidity of each model bilge water prepared is below.

TABLE 6 Bilge Water Emulsion Surfactant Turbidity Turbidity Charge [NTU]Oil Water Emulsion 01 Anionic 264-514 Oil Water Emulsion 02Cationic >1000 Oil Water Emulsion 03 + Anionic 98.7-162  33 g per L NaCl

It is important to note that there are zero suspended solids other thanthose in the emulsion.

FIG. 42 demonstrates the improved model bilge water filtrationproperties of a porous material with a mesostructured sol gel filmcompared to a porous material without a mesostructured sol gel film.FIG. 42 compares the permeability and rejection of two materials, zNanoCA2 (CA2) and 0.1 um PES (Control). The Model Bilge Water was “Oil WaterEmulsion 03+33 g per L NaCl”. Control is a polyethersulfone (PES)membrane with an average pore size of 0.1 microns. CA2 is amesostructured sol gel thin film on a microfiltration membrane with anaverage pore size of 0.1 microns. The mesostructured thin film wascreated from a self assembly solution. The self assembly solution wasprepared by adding cetyl trimethyl ammonium bromide (CTAB) to0.32:0.64:0.04 volumetric parts of tetraethylorthosilicate, ethanol andwater. The amount of CTAB added resulted in a final concentration ofeight weight percent. The self assembly solution was sonicated using aBranson 1500 sonicator for 90 minutes at 40 Celsius. Support membrane isthen rinsed in water, oxidized then coated with the self assemblysolution. The resulting thin film can be annealed via the addition ofalcohol after coating. Using this method, thin films are cured for >48hrs at >40 Celsius. CTAB is a cationic single chain surfactant. Afterpreparation, the emulsion, was filter by two 1″×3″ materials, Control,CA2, in parallel using a homemade cross flow filtration cell intangential flow filtration mode resulting in 5% water recovery.Materials filtered the Bulk solution for at least 10 minutes beforebeginning the experiment. The pressure was 4.0 PSI. Turbidity andpermeability data is reported every 20 minutes in the graphs on top ofFIG. 42. Turbidity and permeability measurements were reported everyhour in the table on the bottom of FIG. 42.

The top graph of FIG. 42 is a plot of the volume of permeates vs. timefor both CA2 and the control filtering Model Bilge Water. The middlegraph of FIG. 42 is a plot of permeate turbidity vs. time for both CA2and the control filtering Model Bilge Water. After 140 minutes, CA2 hadfiltered 47.6% more water than the Control and the CA2 has turbidityrejection of 99.6% compared to 88.5% rejection of turbidity for theControl. This result demonstrates improved model bilge water filtrationproperties of a porous material with a mesostructured sol gel filmcompared to a porous material without a mesostructured sol gel film.

The table in FIG. 42 contains three experiments comparable to the aboveexperiments. The first column is the material being used as a filter.The second column identifies which emulsion is being filtered, AnionicSeawater N; where N is the batch number and Anionic Seawater is preparedusing the method previously described to create ‘Oil Water Emulsion03+33 g per L NaCl’. The third and fourth columns are a measurements ofthe bulk water's and the permeate water's turbidity after one hour. Thefifth column is a measurement of the permeability of the material afterone hour of filtration. The sixth and seventh columns are a measurementsof the bulk water's and the permeate water's turbidity after two hours.The seventh column is a measurement of the permeability of the materialafter two hours of filtration.

The average increase in permeability of CA2 relative to the Control was55.0% after one hour, and 47.6% after two hours. The average turbidityrejection of CA2 was 98.9% after one hour and 98.1% after two hours.This was superior to the Control. The average turbidity rejection ofControl was 76.3% after one hour and 78.1% after two hours.

The charge of the headgroups of the surfactant can be changed toincrease the permeability of the material. FIG. 43 contains a tablewhere the charges of the surfactants comprising the mesostructure havebeen varied. The resulting structures were used to filter an anionicmodel bilge water. To create anionic model bilge water, we created anoil water emulsion using a modified version of Resolution MEPC.107(49)Revised (‘Model Bilge Water’) (Revised guidelines and specifications forpollution prevention equipment for machinery space bilges of ships. MEPC49/22/Add 2. ANNEX 13 Adopted Jul. 18, 2003.) Briefly, 0.9 g of anionicSodium Dodecylbenzene Sulfonic Acid (SDDBSA) was mixed with 178 ml ofTap Water for two minutes on a hot plate at room temperature. Theemulsion was created via the addition of 9 g of SAE 20W-50 Valvoline andwas subsequently stirred for one hour on a hot plate at roomtemperature. Finally, the emulsion was added to Tap Water such that theemulsion was 6 wt % of the final solution. The permeability andrejection of five materials, CTAB 2:1 (+), DDO 2:1 (U), 50/50 CTAB/LA(N), Lauric Acid 2: MTAB 1(−), and the Control (U), filtering anionicmodel bilge water were compared to a Control. Control is apolyethersulfone (PES) membrane with an average pore size of 0.1microns. CTAB 2:1 (+), DDO 2:1 (U), 50/50 CTAB/LA (N), and Lauric Acid2: MTAB 1(−) are mesostructured sol gel thin film on a microfiltrationmembrane with an average pore size of 0.1 microns. The mesostructuredthin film was created from a self assembly solution. The self assemblysolution was prepared by adding surfactant to 0.32:0.64:0.04 volumetricparts of tetraethylorthosilicate, ethanol and water. The amount ofsurfactant added resulted in a final concentration of eight weightpercent. The surfactant(s) used in each material and their relativemolar ratios are listed in Table 7 below.

TABLE 7 Molar Ratio of Surfactant 1 to Chemistry Surfactant 1 Surfactant2 Surfactant 2 CTAB 2:1 (+) Cetyl Trimethyl NONE 1:0 Ammonium BromideDDO 2:1 (U) Dodecanol NONE 1:0 50/50 CTAB/LA Cetyl Trimethyl Lauric Acid1:1 (N) Ammonium Bromide Lauric Acid Myristyl trimethyl Lauric Acid 1:22:MTAB 1 (−) ammonium bromide

Finally, the self assembly solution was sonicated using a Branson 1500sonicator for 90 minutes at 40 Celsius. Support membrane is then rinsedin water, oxidized then coated with the self assembly solution. Theresulting thin film can be annealed via the addition of alcohol aftercoating. Using this method, thin films are cured for >48 hrs at >40Celsius. After preparation, the emulsion, was filtered by two of the1″×3″ materials: CTAB 2:1 (+), DDO 2:1 (U), 50/50 CTAB/LA (N), or LauricAcid 2:MTAB 1 (−) and one 1″×3″ Control material in parallel using threehomemade cross flow filtration cell in tangential flow filtration moderesulting in ˜5% water recovery. Materials filtered the Bulk solutionfor at least 10 minutes before beginning the experiment. The pressurewas 4.0 PSI. Permeability and turbidity reported were measured after onehour.

The table in FIG. 43 compares four porous materials comprising fourdifferent mesostructured sol gel films to a porous material without amesostructured sol gel film, Control. The first column of the table(‘Chemistry’) identifies the material's chemistry. The second column ofthe table (‘Surfactant Charge’) identifies the surface charge of eachmaterial. The third column of the table (‘GFD/PSI’) reports thepermeability of each material in gallons per square feet per day per psi(GFDP). The fourth column of the table (‘Turbidity’) reports theturbidity of the water filtered by the material. By changing thesurfactant in the thin film mesostructure, the permeability could bevaried from 2.48 GFDP to 13.0 GFDP. Two materials had permeabilitygreater than the control, 7.38 gfdp. Those materials were DDO 2:1 (U)(13.0 GFDP) and Lauric Acid 2:MTAB 1 (−) (9.29 GFDP). For themesostructured samples, turbidity decreased with permeability. Thecorrelation of rejection of turbidity and permeability suggests that thedifferences in performance are a result of differences in pore size.Filtration was unstable using the Control. In two of three samples, theturbidity of filtrate was greater than or equal to the Model Bilge Waterbeing filtered. All of the permeates from the mesostructured thin filmmaterials had turbidity less than both the Model Bilge Water turbidityand the average permeate of the Control, 399 NTU +601/−396.

Coatings of the present invention improve ultrafiltration of anemulsion. To produce the emulsion, the following protocol was used.Briefly, a solution of 500 ml of reverse osmosis water, containing 200milligrams of sodium chloride, 100 milligrams of calcium chloride and500 milligrams of sodium dodecylbenzene sulfonic acid (SDDBSA) wasprepared. The solution was mixed for two minutes on a hot plate at roomtemperature using a stir bar. The pH of the solution was adjusted to 9using sodium hydroxide. An emulsion was created via the addition of 1gram to 6 grams of vegetable oil (‘Veggie Oil’). The emulsion wassubsequently stirred for one hour on a hot plate at room temperature.Finally, the emulsion was added to 1500 liters of pH 9 reverse osmosiswater. The resulting solution was circulated with a small pump to enablemixing.

After preparation, the emulsion was filtered by two 1″×3″ materials, CA2and a Control ultrafiltration membrane with a molecular weight cutoff35,000 daltons. Filtration through the two materials was done inparallel using a homemade crossflow filtration cell in a dead end mode,meaning 100% water recovery. Materials filtered the Bulk solution for atleast 10 minutes before beginning the experiment. The pressure was 5.5PSI. All turbidity and permeability data is after one hour offiltration.

In one experiment, the filtration performances (permeability andturbidity rejection) of two materials, PS35 k MWCO and CA2 PS35 k MWCOwas compared. CA2 PS35 k MWCO is a mesostructured sol gel thin film onthe same 35,000 molecular weight polysulfone (PS 35 k MWCO) membrane.The mesostructured thin film was created from a self assembly solution.The self assembly solution was prepared by adding cetyl trimethylammonium bromide (CTAB) to 0.32:0.64:0.04 volumetric parts oftetraethylorthosilicate, ethanol and water. The amount of CTAB addedresulted in a final concentration of eight weight percent. The selfassembly solution was sonicated using a Branson 1500 sonicator for 90minutes at 40 Celsius. Support membrane is then rinsed in water,oxidized then coated with the self assembly solution. The resulting thinfilm can be annealed via the addition of alcohol after coating. Usingthis method, thin films are cured for >48 hrs at >40 Celsius. CTAB is acationic single chain surfactant.

TABLE 8 Membrane GFD per PSI Turbidity Rejection CA2 PS35k MWCO 3.1199.8% PS35k MWCO 1.13 99.2%

Table 8 compares both the permeability and the turbidity rejection ofPS35 k MWCO and CA2 PS35 k MWCO. PS35 k MWCO is a porous materialwithout a mesostructure and CA2 PS35 k MWCO is a porous material with amesostructured sol gel film. The first column (‘membrane’) identifieswhich material was used for the filtration. The second column (GFD perPSI) reports the permeability of the materials after one hour offiltration in gallons per square foot per day per psi (GFDP). The finalcolumn (‘turbidity rejection’) reports the rejection of turbidity inpercentage after one hour of filtration. Turbidity is measured for thefeedwater (NTU_(feed)) and the permeate (NTU_(permeate)) for bothmaterials in NTU. Rejection is calculated according to the equationbelow:

${Rejection} = \frac{{NTU}_{feed} - {NTU}_{permeate}}{{NTU}_{feed}}$

Table 8 shows that the permeability of the porous material with amesostructured sol gel thin film (CA2 PS35 k MWCO) has a permeability2.75× greater than porous material without a mesostructured sol gel thinfilm (PS35 k MWCO). A comparison of the turbidity rejection between thetwo materials reveals comparable results. The porous material with themesostructured sol gel thin film (CA2 PS35 k MWCO) has a turbidityrejection of 99.8% and the porous material without the mesostructuredsol gel thin film (PS35 k MWCO) has a turbidity rejection of 99.2%. Thefeed water was 1.513 NaBBS (500 ppm), 9.14 g Veg Oil (3000 ppm), 3000.39g RO H20, pH 9, and had a turbidity of greater than 1000 (NTU_(feed)).

One application of porous materials with a mesostructured sol gel thinfilms is to improve the filtration rate of laundry water in comparisonto porous materials without a mesostructured sol gel thin films. Thewashing machine used was a Whirpool top loading washing machine. Theamount of detergent (“all” free & clear), was used at the recommendedlevel by the manufacturer. The load was a cold water, color wash ofclothes mostly worn for office work. Laundry water (1.5 gallons) wascollected between 8 and 16 minutes into the first cycle. The turbidityand conductivity of the laundry water were measured daily due to thecontinuous settling of particles within the water. Table 9 shows theresults of measurements of the turbidity and conductivity of laundrywater after 1, 2 and 4 days. Turbidity was measured using a 2100Portable Turbidimeter from Hach. The water conductivity was measuredusing an Oakton Acron CON 6 portable conductivity meter.

TABLE 9 Waste Water Characterization DAY Conductivity NTU Laundry WaterSample 1 1 1563 uS 71.0 Laundry Water Sample 1 2 1555 uS 66.2 LaundryWater Sample 1 4 1612 uS 49.0

FIG. 44A is a picture of a beaker with 180 ml of the sourced wash waterhaving a turbidity (i.e. water clarity) of 71 NTU. FIG. 44B is a picturecomparing approximately 15 mls of tap water (for reference), zNano CA1membrane filtered laundry water (described later), and unfilteredlaundry water. This comparison reveals that the zNano CA 1 membraneremoves most of the turbidity (cloudiness) of the laundry water. Belowis a table characterizing both the turbidity and the conductivity of atypical waste laundry water sample over a four day period. The wastelaundry water sample is the same in each row. The quality of the laundrywater sample improves due to the slow settling of solids.

After collection, the sample was filtered by three 1″×3″ materials, CA2,CA1 and a Control material. Filtration through the three materials wasdone in parallel using a homemade crossflow filtration cell in a deadend mode, meaning 100% water recovery. Materials filtered the Bulksolution for at least 10 minutes before beginning the experiment. Thepressure was 5.5 PSI. All conductivity, turbidity and permeability datais after one hour of filtration. Control is a polyethersulfone (PES)membrane with an average pore size of 0.1 microns. CA1 is amesostructured sol gel thin film on a microfiltration membrane with anaverage pore size of 0.1 microns. The mesostructured thin film wascreated from a self assembly solution. The self assembly solution wasprepared by adding cetyl trimethyl ammonium bromide (CTAB) to0.48:0.48:0.04 volumetric parts of tetraethylorthosilicate, ethanol andwater. The amount of CTAB added resulted in a final concentration ofeight weight percent. The self assembly solution was sonicated using aBranson 1500 sonicator for 90 minutes at 40 Celsius. Support membrane isthen rinsed in water, oxidized then coated with the self assemblysolution. The resulting thin film can be annealed via the addition ofalcohol after coating. Using this method, thin films are cured for >48hrs at >40 Celsius. CA2 is a mesostructured sol gel thin film on amicrofiltration membrane with an average pore size of 0.1 microns. Themesostructured thin film was created from a self assembly solution. Theself assembly solution was prepared by adding cetyl trimethyl ammoniumbromide (CTAB) to 0.32:0.64:0.04 volumetric parts oftetraethylorthosilicate, ethanol and water. The amount of CTAB addedresulted in a final concentration of eight weight percent. The selfassembly solution was sonicated using a Branson 1500 sonicator for 90minutes at 40 Celsius. Support membrane is then rinsed in water,oxidized then coated with the self assembly solution. The resulting thinfilm can be annealed via the addition of alcohol after coating. Usingthis method, thin films are cured for >48 hrs at >40 Celsius. CTAB is acationic single chain surfactant.

TABLE 10 GFD Turbidity Conductivity Membrane per PSI Rejection RejectionCA2 5.78 97.2% −0.63% CA1 4.30 97.00% 0.78% Control 4.02 98.7% 0.15%

Table 10 compares the permeability, turbidity rejection, andconductivity rejection of CA2, CA1, and the Control. The first column(‘membrane’) identifies which material was used for the filtration. Thesecond column (GFD per PSI) reports the permeability of the materialsafter one hour of filtration in gallons per square foot per day per psi(GFDP). The third column (‘turbidity rejection’) reports the rejectionof turbidity in percentage after one hour of filtration. Turbidity ismeasured for the feedwater (NTU_(feed)) and the permeate(NTU_(permeate)) for both materials in NTU.

Rejection is calculated according to the equation below:

${Rejection} = \frac{{NTU}_{feed} - {NTU}_{permeate}}{{NTU}_{feed}}$

The fourth column (‘conductivity rejection’) reports the rejection ofconductivity in percentage after one hour of filtration. Conductivitymeasures total dissolved solids within a water sample in ppm (parts permillion), and is reported for the feedwater (ppm_(feed)) and thepermeate (ppm_(permeate)) from both materials. Rejection is calculatedaccording to the equation below:

${Rejection} = \frac{{PPM}_{feed} - {PPM}_{permeate}}{{PPM}_{feed}}$

The data in Table 10 confirms that the filtration properties of a porousmaterial with a mesostructured sol gel film are improved compared to aporous material without a mesostructured sol gel film when filteringlaundry water samples. The permeability of the CA2 and the CA1 materialwere 43.8% and 7.0% higher relative to the Control. All three materialshave comparable turbidity rejection within 98%+1-1% and conductivityrejection of 0%+1-1%.

Table 11 describes the laundry water samples filtered by the threematerials. Column one (‘laundry water samples’) identifies the sample.Column two (‘turbidity’) is a measure of the turbidity of the laundrywater samples (NTU_(feed)). Column three (‘conductivity’) is a measureof the total dissolved solids of the laundry water samples (ppm_(feed)).The average turbidity of the laundry water samples was 83.3 NTU and theaverage conductivity was 717 ppm.

TABLE 11 laundry water samples Turbidity Conductivity Sample 1 186 720Sample 2 29.1 674 Sample 3 34.4 758 Average 83.3 717

FIGS. 45A and 45B demonstrate the improved filtration properties of aporous material with a mesostructured sol gel film compared to and aporous material without a mesostructured sol gel film when filtering35,000 Dalton polyethylene glycol (PEG 35 k). The PEG 35 k Solution isprepared by mixing PEG 35 k with reverse osmosis water resulting in asolution with a final PEG 35 k of 1.0 wt %. After preparation of the PEG35 k Solution, the sample was filtered by three 1″×3″ materials, CA2PS100 k, CA1 PS100 k and a PS100 k material. Filtration through thethree materials was done in parallel using a homemade crossflowfiltration cell in a dead end mode, meaning 100% water recovery.Materials filtered the Bulk solution for at least 10 minutes beforebeginning the experiment. The pressure was 5.5 PSI. All PEG 35 kconcentration measurements are performed using refractometry. PS100 k isa polysulfone ultrafiltration membrane with a molecular weight cutoff of100,000 Daltons. CA1 PS100 k is a mesostructured sol gel thin film on apolysulfone ultrafiltration membrane with a molecular weight cutoff of100,000 Daltons. The mesostructured thin film was created from a selfassembly solution. The self assembly solution was prepared by addingcetyl trimethyl ammonium bromide (CTAB) to 0.48:0.48:0.04 volumetricparts of tetraethylorthosilicate, ethanol and water. The amount of CTABadded resulted in a final concentration of eight weight percent. Theself assembly solution was sonicated using a Branson 1500 sonicator for90 minutes at 40 Celsius. Support membrane is then rinsed in water,oxidized then coated with the self assembly solution. The resulting thinfilm can be annealed via the addition of alcohol after coating. Usingthis method, thin films are cured for >48 hrs at >40 Celsius. CA2 PS100k is a mesostructured sol gel thin film on a polysulfone ultrafiltrationmembrane with a molecular weight cutoff of 100,000 Daltons. Themesostructured thin film was created from a self assembly solution. Theself assembly solution was prepared by adding cetyl trimethyl ammoniumbromide (CTAB) to 0.32:0.64:0.04 volumetric parts oftetraethylorthosilicate, ethanol and water. The amount of CTAB addedresulted in a final concentration of eight weight percent. The selfassembly solution was sonicated using a Branson 1500 sonicator for 90minutes at 40 Celsius. Support membrane is then rinsed in water,oxidized then coated with the self assembly solution. The resulting thinfilm can be annealed via the addition of alcohol after coating. Usingthis method, thin films are cured for >48 hrs at >40 Celsius. CTAB is acationic single chain surfactant.

FIG. 45A is a schematic illustrating the CA2 PS100 k and the CA1 PS100 kmaterials. Specifically, a surfactant templated thin film is assembledon a porous surface. FIG. 45B is a schematic of an embodiment of amesostructured sol gel film. The material is a multiscale self assembledmaterial. On the microscale is the assembly of the two films: A and B.In this embodiment, A is a nanostructured thin film and B is a porousmembrane. On the nanoscale is the assembly of alternating lamella ofsilica and lipid bilayers illustrated in A. Table 12 shows the increasein rejection of 35,000 molecular weight poly ethylene glycol by thematerial after the creation of the self assembled film on the poroussurface. Specifically, Table 12 compares the PEG 35 k rejection of ofCA2 PS100 k, CA1 PS100 k, and a PS100 k. The first column (‘membrane’)identifies which material was used for the filtration. The second column(MW) reports the molecular weight of the polyethylene glycol (PEG) inthe solution to be filtered. The third column (‘turbidity rejection’)reports the rejection of PEG in percentage after one hour of filtration.PEG concentration, measured using refractometry, is measured in the feed(brix_(feed)) and in the permeate (brix_(permeate)) for all materials.Rejection is calculated according to the equation below:

${Rejection} = \frac{{brix}_{feed} - {brix}_{permeate}}{{brix}_{feed}}$

As expected, the PS100 k rejects 0% of 35,000 molecular weight PEG. Theaddition of either mesostructured sol-gel film, CA2 or CA1, results in amaterial which rejects 80% of PEG 35 k.

TABLE 12 Membrane MW Rejection CA2 PS100k 35,000 80.00% CA1 PS100k35,000 80.00% PS100k 35,000 0.0%

A porous material with a mesostructured sol gel film compared to aporous material without a mesostructured sol gel film exhibits improvedfiltration properties when filtering laundry water samples. Aftercollection of the laundry water sample, the sample was filtered by three1″×3″ materials, CA2 PS100 k, CA1 PS100 k and a PS100 k material.Filtration through the three materials was done in parallel using ahomemade crossflow filtration cell in a dead end mode, meaning 100%water recovery. Materials filtered the Bulk solution for at least 10minutes before beginning the experiment. The pressure was 5.5 PSI. Allconductivity, turbidity and permeability data is after one hour offiltration. PS100 k is a polysulfone ultrafiltration membrane with amolecular weight cutoff of 100,000 Daltons. CA1 PS100 k is amesostructured sol gel thin film on a polysulfone ultrafiltrationmembrane with a molecular weight cutoff of 100,000 Daltons. Themesostructured thin film was created from a self assembly solution. Theself assembly solution was prepared by adding cetyl trimethyl ammoniumbromide (CTAB) to 0.48:0.48:0.04 volumetric parts oftetraethylorthosilicate, ethanol and water. The amount of CTAB addedresulted in a final concentration of eight weight percent. The selfassembly solution was sonicated using a Branson 1500 sonicator for 90minutes at 40 Celsius. Support membrane is then rinsed in water,oxidized then coated with the self assembly solution. The resulting thinfilm can be annealed via the addition of alcohol after coating. Usingthis method, thin films are cured for >48 hrs at >40 Celsius. CA2 PS100k is a mesostructured sol gel thin film on a polysulfone ultrafiltrationmembrane with a molecular weight cutoff of 100,000 Daltons. Themesostructured thin film was created from a self assembly solution. Theself assembly solution was prepared by adding cetyl trimethyl ammoniumbromide (CTAB) to 0.32:0.64:0.04 volumetric parts oftetraethylorthosilicate, ethanol and water. The amount of CTAB addedresulted in a final concentration of eight weight percent. The selfassembly solution was sonicated using a Branson 1500 sonicator for 90minutes at 40 Celsius. Support membrane is then rinsed in water,oxidized then coated with the self assembly solution. The resulting thinfilm can be annealed via the addition of alcohol after coating. Usingthis method, thin films are cured for >48 hrs at >40 Celsius. CTAB is acationic single chain surfactant.

Table 13 compares the permeability, turbidity rejection, andconductivity rejection of CA2 PS100 k, CA1 PS100 k, and a PS100 k. Thefirst column (‘membrane’) identifies which material was used for thefiltration. The second column (GFD per PSI) reports the permeability ofthe materials after one hour of filtration in gallons per square footper day per psi (GFDP). The third column (‘turbidity rejection’) reportsthe rejection of turbidity in percentage after one hour of

TABLE 13 GFD Turbidity Conductivity Membrane per PSI Rejection RejectionCA2 PS100k 5.47 99.11% 2.22% CA1 PS100k 1.36 98.51% 2.91% PS100k 3.5599.22% 0.56%filtration. Turbidity is measured for the feedwater (NTU_(feed)) and thepermeate (NTU_(permeate)) for both materials in NTU. Rejection iscalculated according to the equation below:

${Rejection} = \frac{{NTU}_{feed} - {NTU}_{permeate}}{{NTU}_{feed}}$

The fourth column (‘conductivity rejection’) reports the rejection ofconductivity in percentage after one hour of filtration. Conductivitymeasures total dissolved solids within a water sample in ppm (parts permillion), and is reported for the feedwater (ppm_(feed)) and thepermeate (ppm_(permeate)) from both materials. Rejection is calculatedaccording to the equation below:

${Rejection} = \frac{{PPM}_{feed} - {PPM}_{permeate}}{{PPM}_{feed}}$

The data in the Table 13 confirms that the filtration properties of aporous material with a mesostructured sol gel film are improved comparedto a porous material without a mesostructured sol gel film whenfiltering laundry water samples. The permeability of the CA2 PS100 k andthe CA1 PS100 k material were 54.1% and −61.7% higher relative to aPS100 k. All three materials have comparable turbidity rejection within99%+1-0.5%. The conductivity rejection of the CA2 PS100 k and CA1 PS100k membranes was 2.57%+1-0.34% compared to 0.56% for a PS100 k. Thedifference conductivity rejection of the CA2 PS100 k and CA1 PS100 k,2.57%, is statistically significant in comparison to the results for thePS100 k and the materials in Tables 10-11.

Table 14 describes the laundry water samples filtered by the threematerials. Column one (‘laundry water samples’) identifies the sample.Column two (‘turbidity’) is a measure of the turbidity of the laundrywater samples (NTU_(feed)). Column three (‘conductivity’) is a measureof the total dissolved solids of the laundry water samples (ppm_(feed)).The average turbidity of the laundry water samples was 49.9 NTU and theaverage conductivity was 710 ppm.

TABLE 14 Feed Water Turbidity Conductivity Sample 1 46.9 742 Sample 244.2 689 Sample 3 58.7 700 Average 49.9 710

Mesostructured thin films on porous materials have a unique separationmechanism when used for forward osmosis. Typical forward osmosis/reverseosmosis membranes use the solution diffusion mechanism to separate waterand solutes. FIG. 46 demonstrates how a mesostructured thin film on aporous material, CA1, has a process dependent separation mechanism. CA1is a mesostructured sol gel thin film on a microfiltration membrane withan average pore size of 0.1 microns. The mesostructured thin film wascreated from a self assembly solution. The self assembly solution wasprepared by adding cetyl trimethyl ammonium bromide (CTAB) to0.48:0.48:0.04 volumetric parts of tetraethylorthosilicate, ethanol andwater. The amount of CTAB added resulted in a final concentration ofeight weight percent. The self assembly solution was sonicated using aBranson 1500 sonicator for 90 minutes at 40 Celsius. Support membrane isthen rinsed in water, oxidized then coated with the self assemblysolution. The resulting thin film can be annealed via the addition ofalcohol after coating. Using this method, thin films are cured for >48hrs at >40 Celsius. The two different processes are forward osmosis andreverse osmosis. Using a typical cellulose triacetate or aromatic polyamide membrane, the rejection of solutes would be comparable in both aforward osmosis and a reverse osmosis process, e.g. >90% rejection ofNaCl.

For forward osmosis measurements, salt backflux is an important membraneparameter. It is a measure of how much draw solute is permeating throughthe material in the opposite direction of water flux. Salt backflux iscalculated using the following method. First, the both the conductivityand the volume of the feed water are measured at an initial time and afinal time. The conductivity measurements G are converted toconcentration C using a conversion factor:

$C = {0.64{\frac{g/L}{{mS}/{cm}} \cdot G}}$

The reverse salt flux is found the calculating the change in mass ofsalt in the feed over time, as follows:

$L = \frac{\left( {{V_{f,{t\; 2}}C_{f,{t\; 2}}} - {V_{f,{t\; 1}}C_{f,{t\; 1}}}} \right)}{\left( {t_{2} - t_{1}} \right) \cdot A}$

Where V is the volume of the feed water, C is the concentration of saltin the feed water, A is the area of the membrane, and t is time.

FIG. 46 shows the results of a CA1 material in a forward osmosisprocess. A CA1 material with surface area equal to 0.037 was mountedinto a home built test cell. The average pressure drop from the feed tothe brine was 3.0 psi. The concentration of the brine was 2M NaCl. Theflow rate of the feed was 60 Gallons per Hour and the flow rate of thebrine was 7 gallons per hour. In data not shown, the temperaturecorrected average flux over three experiments at the end of one hour was59.7 liters per meter squared per hour and the average salt backflux was1.9 grams per meter squared per hour. The y-axis on the left hand sidecorresponds to the diamond shaped markers and reports the flux throughthe CA1 material. The y-axis on the right hand side corresponds to thesquare markers and reports the urea rejection by the CA1 material. Theaverage flux over a 90 minute period was 70.18 liters per meter squaredper hour. The concentration of urea in the feed water was 3 grams perliter. In the forward osmosis experiment, the rejection of urea relativeto the solution flux across the membrane was 67.55%. This is comparableto commercial forward osmosis membranes.

A reverse osmosis process (RO) separation using a CA1 material preparedusing the same method used to prepare the CA1 material measured in FIG.46 was also performed. A 10,000 Dalton (i.e. 10,000 molecular weight)polyethylene glycol (PEG 10 k) solution was prepared for the ROseparation. The PEG 10 k Solution is prepared by mixing PEG 10 k withreverse osmosis water resulting in a solution with a final PEG 10 k of1.0 wt %. After preparation of the PEG 10 k Solution, the sample wasfiltered by one 1″×3″ piece of CA1 material. Filtration through thethree materials was done in parallel using a homemade crossflowfiltration cell in tangential flow filtration mode, meaning 5% waterrecovery. The CA1 materials filtered PEG 10 k solution for at least 10minutes before beginning the experiment. The pressure was 4.0 PSI. Thepressure drop across the membrane was 2-4 psi. All PEG 10 kconcentration measurements were performed using refractometry. Undertangential flow filtration the CA1 material displayed no rejection (0%)of 10 k PEG in an RO separation. A typical forward osmosis materialrejects >99% of 10 k PEG. This demonstrates that the mesostructuredsol-gel films on porous supports do not use the solution diffusionmechanism. One plausible mechanism is the electrostatic mechanism. Indata not shown, replacing the cationic surfactant, CTAB, with annonionic surfactant, e.g. dodecanol, in the mesostructure eliminatesflux from osmotic gradients.

The surfactant composition of mesostructured thin films on porousmaterials can be varied, changing the performance of the material whenused for forward osmosis. Membranes were prepared the same way as CA2except the surfactant(s) were not CTAB. Table 15 shows the results ofvarying the surfactant in the mesostructured sol gel thin film on theporous material when used in a forward osmosis process. Tested materialshad a surface area equal to 0.002 square meters using a home built testcell.

TABLE 15 Feed Flow Brine Flow g/L Membrane Feed (ml/min) (ml/min) ΔP FOFlux LMH Wt % Solute (1 hr; 3 hr) 1:0 MTAB RO 60 12 2 193 10 NaCl −0.3;−0.3 2:1 MTAB RO 60 12 2 156 10 NaCl −0.4; −0.3 50:50 M:L RO 60 12 2 8910 NaCl 0.1; 4.1 1:2 Lauric RO 60 12 2 147 10 NaCl 0.48; 0.17 0:1 LauricRO 60 12 2 116 10 NaCl −0.2; −0.3 DLPC RO 60 12 2 77 10 NaCl 1.3; 1.8

The material tested is listed in the first column (‘Membrane’). Thesecond column (‘Feed’) is the feed water which was always reverseosmosis water. The third and fourth column are the flow rate of the feedwater and the brine water respectively. Delta P is the pressure drop,2.0 PSI, across the test cell from the feed to the brine. The sixthcolumn (‘FO Flux LMH’) is the flux through the material. The seventh(‘Wt %’) and eighth (‘Solute’) columns are 10 wt % and NaCl for allsamples. The final column (g/L) is the ratio of grams of NaCl flux inthe opposite direction of Liters of water flux.

TABLE 16 Molar Ratio of Surfactant 1 to Chemistry Surfactant 1Surfactant 2 Surfactant 2 1:0 MTAB Myristyl trimethyl Lauric Acid 1:0ammonium bromide 2:1 MTAB Myristyl trimethyl Lauric Acid 2:1 ammoniumbromide 50:50 M:L Myristyl trimethyl Lauric Acid 1:1 ammonium bromide1:2 Lauric Acid Myristyl trimethyl Lauric Acid 1:2 ammonium bromide 0:1Lauric Acid Myristyl trimethyl Lauric Acid 0:1 ammonium bromide

Table 16 gives the chemical name(s) and the molar ratio(s) ofsurfactants in the materials listed in the Membrane column. Only two ofthe materials have positive ratios of grams NaCl per Liter of water.Those materials were 1:2 Lauric and 50:50 M:L. Because they demonstratedsalt flux in the opposite direction of water flux, it is confirmed thatthey are demonstrating forward osmosis.

Compared to DLPC, a material with a mesostructure composed of asurfactant with two chains, the 50:50 M:L and 1:2 Lauric produce 15.6%and 90.9% greater flux under identical operating conditions. Lower saltback flux relative to water flux is more desirable for forward osmosismembranes. After one hour, the salt back flux of 50:50 M:L and 1:2Lauric are 7.7% and 37% of the salt back flux of the DLPC. After threehours, the salt back flux of 50:50 M:L and 1:2 Lauric are 228% and 9.4%of the salt back flux of the DLPC. The increased flux and decreased saltbackflux demonstrates how these materials are improvements over a DLPCbased structure for forward osmosis.

The porous materials containing a mesostructured sol-gel film describedwithin this application can be used in standard configurations for watertreatment. One example of a standard configuration is a spiral woundelement, which has been manufactured using a porous material containinga mesostructured sol-gel film described herein. This type of watertreatment element could be used for any water treatment application suchas wastewater treatment, bilge water treatment, emulsions, concentrationof proteins, desalination, etc. FIG. 47 is a simple flow diagram of atwo stage microfiltration/ultrafiltration, reverse osmosis watertreatment system. Any porous material containing a mesostructure in astandard water filtration configuration is used to pretreat the hightotal organic carbon (TOC) wastewater before it is filtered by astandard reverse osmosis membrane. The material, manufactured into astandard water treatment element such as a spiral wound element or ahollow fiber membrane, can be used in any water treatment system.

Table 17 contains filtration results of a 4.0″×40″ spiral wound elementmanufactured from a 40″×25′sheet of porous material containing amesostructured sol-gel film, as described within this application, by acontract manufacturer. CA1 PS10 k is a mesostructured sol gel thin filmon a ultrafiltration membrane with a molecular weight cutoff of 10,000Dalton polyethylene glycol. The mesostructured thin film was createdfrom a self assembly solution. The self assembly solution was preparedby adding cetyl trimethyl ammonium bromide (CTAB) to 0.48:0.48:0.04volumetric parts of tetraethylorthosilicate, ethanol and water. Theamount of CTAB added resulted in a final concentration of eight weightpercent. The self assembly solution was sonicated using a Branson 1500sonicator for 90 minutes at 40 Celsius. The support membrane is thenrinsed in water, oxidized then coated with the self assembly solution.The resulting thin film can be annealed via the addition of alcoholafter coating. Using this method, thin films are cured for >48 hrsat >40 Celsius.

A comparison of the unfiltered wastewater and the filtered wastewater isshown in Table 17. Column 1 is the Water Source. Column 2 is theturbidity of the water measured in NTU. Column 3 is a calculation ofturbidity rejection relative to the wastewater. Column 4 is theconductivity of the water measured in part per million (ppm). Column 5is a calculation of conductivity rejection relative to the wastewater.The element removed 91.9% of turbidity and 14.9% of conductivity.

TABLE 17 Water Turbidity Turbidty Conductivity Source NTU RejectionConductivity Rejection Wastewater 354; 354; 354 N/A 424 ppm N/A CA1 10kPS 28.5; 28.7; 28.8 91.9% 361 ppm 14.9%

SPECIFIC EMBODIMENTS OF THE INVENTION

The CA1 PS35 k is a mesostructured sol gel thin film on anultrafiltration membrane resulting in a material with a MWCO of 35,000Daltons. The mesostructured thin film was created from a self assemblysolution. The self assembly solution was prepared by adding cetyltrimethyl ammonium bromide (CTAB) to 0.48:0.48:0.04 volumetric parts oftetraethylorthosilicate, ethanol and water. The amount of CTAB addedresulted in a final concentration of eight weight percent. The selfassembly solution was sonicated using a Branson 1500 sonicator for 90minutes at 40 Celsius. Support membrane is then rinsed in water,oxidized then coated with the self assembly solution. The resulting thinfilm can be annealed via the addition of alcohol after coating. Usingthis method, thin films are cured for >48 hrs at >40 Celsius.

The CA2 PS35 k is a mesostructured sol gel thin film on anultrafiltration membrane resulting in a material with a MWCO of 35,000Daltons. The mesostructured thin film was created from a self assemblysolution. The self assembly solution was prepared by adding cetyltrimethyl ammonium bromide (CTAB) to 0.32:0.64:0.04 volumetric parts oftetraethylorthosilicate, ethanol and water. The amount of CTAB addedresulted in a final concentration of eight weight percent. The selfassembly solution was sonicated using a Branson 1500 sonicator for 90minutes at 40 Celsius. Support membrane is then rinsed in water,oxidized then coated with the self assembly solution. The resulting thinfilm can be annealed via the addition of alcohol after coating. Usingthis method, thin films are cured for >48 hrs at >40 Celsius.

The CA1 PS100 k is a mesostructured sol gel thin film on a polysulfoneultrafiltration membrane with a molecular weight cutoff of 100,000Daltons. The mesostructured thin film was created from a self assemblysolution. The self assembly solution was prepared by adding cetyltrimethyl ammonium bromide (CTAB) to 0.48:0.48:0.04 volumetric parts oftetraethylorthosilicate, ethanol and water. The amount of CTAB addedresulted in a final concentration of eight weight percent. The selfassembly solution was sonicated using a Branson 1500 sonicator for 90minutes at 40 Celsius. Support membrane is then rinsed in water,oxidized then coated with the self assembly solution. The resulting thinfilm can be annealed via the addition of alcohol after coating. Usingthis method, thin films are cured for >48 hrs at >40 Celsius.

The CA2 PS100 k is a mesostructured sol gel thin film on a polysulfoneultrafiltration membrane with a molecular weight cutoff of 100,000Daltons. The mesostructured thin film was created from a self assemblysolution. The self assembly solution was prepared by adding cetyltrimethyl ammonium bromide (CTAB) to 0.32:0.64:0.04 volumetric parts oftetraethylorthosilicate, ethanol and water. The amount of CTAB addedresulted in a final concentration of eight weight percent. The selfassembly solution was sonicated using a Branson 1500 sonicator for 90minutes at 40 Celsius. Support membrane is then rinsed in water,oxidized then coated with the self assembly solution. The resulting thinfilm can be annealed via the addition of alcohol after coating. Usingthis method, thin films are cured for >48 hrs at >40 Celsius.

The CA1 is a mesostructured sol gel thin film on a microfiltrationmembrane with an average pore size of 0.1 microns. The mesostructuredthin film was created from a self assembly solution. The self assemblysolution was prepared by adding cetyl trimethyl ammonium bromide (CTAB)to 0.48:0.48:0.04 volumetric parts of tetraethylorthosilicate, ethanoland water. The amount of CTAB added resulted in a final concentration ofeight weight percent. The self assembly solution was sonicated using aBranson 1500 sonicator for 90 minutes at 40 Celsius. Support membrane isthen rinsed in water, oxidized then coated with the self assemblysolution. The resulting thin film can be annealed via the addition ofalcohol after coating. Using this method, thin films are cured for >48hrs at >40 Celsius.

The CA2 is a mesostructured sol gel thin film on a microfiltrationmembrane with an average pore size of 0.1 microns. The mesostructuredthin film was created from a self assembly solution. The self assemblysolution was prepared by adding a surfactant, either cetyl trimethylammonium bromide (CTAB) or a combination of myristyl trimethyl ammoniumbromide (MTAB) and lauric acid (LA) from molar ratios of 1:0 to 0:1, at0.32:0.64:0.04 volumetric parts of tetraethylorthosilicate, ethanol andwater. The amount of surfactant added resulted in a final concentrationof eight weight percent. The self assembly solution was sonicated usinga Branson 1500 sonicator for 90 minutes at 40 Celsius. Support membraneis then rinsed in water, oxidized then coated with the self assemblysolution. The resulting thin film can be annealed via the addition ofalcohol after coating. Using this method, thin films are cured for >48hrs at >40 Celsius.

The CA1 PS10 k is a mesostructured sol gel thin film on aultrafiltration membrane with a molecular weight cutoff of 10,000 Daltonpolyethylene glycol. The mesostructured thin film was created from aself assembly solution. The self assembly solution was prepared byadding cetyl trimethyl ammonium bromide (CTAB) to 0.48:0.48:0.04volumetric parts of tetraethylorthosilicate, ethanol and water. Theamount of CTAB added resulted in a final concentration of eight weightpercent. The self assembly solution was sonicated using a Branson 1500sonicator for 90 minutes at 40 Celsius. Support membrane is then rinsedin water, oxidized then coated with the self assembly solution. Theresulting thin film can be annealed via the addition of alcohol aftercoating. Using this method, thin films are cured for >48 hrs at >40Celsius.

Although the invention has been described in detail with particularreference to the described embodiments, other embodiments can achievethe same results. Variations and modifications of the present inventionwill be obvious to those skilled in the art and it is intended to coverall such modifications and equivalents. The entire disclosures of allpatents and publications cited above are hereby incorporated byreference.

1. A hydrophilic coating for a porous material, said coating comprisingan inorganic material derived from a sol-gel precursor.
 2. The coatingof claim 1 wherein said inorganic material comprises silica and/oralumina.
 3. The coating of claim 1 comprising a stabilized surfactantmesostructure, said stabilized surfactant mesostructure comprising oneor more single chain surfactants.
 4. (canceled)
 5. The coating of claim3 wherein said stabilized surfactant mesostructure comprises betweenapproximately 1 and approximately 20 wt % surfactants.
 6. A filtercomprising a porous material coated with the coating of claim
 1. 7.(canceled)
 8. The filter of claim 6 wherein an average pore size of thefilter is less than an average pore size of said porous material. 9.(canceled)
 10. The filter of claim 6 wherein said porous material has anaverage pore size between 0.002 microns and approximately 0.4 microns.11. (canceled)
 12. The filter of claim 6 wherein said porous materialhas a molecular weight cutoff between approximately 100 daltons andapproximately 500,000 daltons.
 13. (canceled)
 14. The filter of claim 6wherein said porous material comprises polyethersulfone (PES),polysulfone (PS), polyvinyldiflouride (PVDF), poly acrylic nitrile(PAN), or a blend thereof. 15.-22. (canceled)
 23. The filter of claim 6wherein turbidity of a filtrate filtered by said filter is at least 10%lower than turbidity of a filtrate filtered by said porous material. 24.(canceled)
 25. (canceled)
 26. (canceled)
 27. The filter of claim 6comprising a partially or completely electrostatic separation mechanism.28. The filter of claim 6 formed into an element used in a watertreatment system.
 29. The filter of claim 28 wherein said elementcomprises a spiral wound element.
 30. The filter of claim 28 whereinsaid water treatment system comprises a two stage process comprising amicrofiltration/ultrafiltration stage and a reverse osmosis stage. 31.The filter of claim 6 useful for filtering a fluid selected from thegroup consisting of wastewater, wastewater comprising surfactants,wastewater comprising an emulsion, bilge water, grey water, laundrywater, and emulsions.
 32. A forward osmosis membrane comprising thefilter of claim
 6. 33. The forward osmosis membrane of claim 32 having amolecular weight cutoff when used in a reverse osmosis configurationwhich is at least an order of magnitude different than a molecularweight cutoff when used in a forward osmosis configuration.
 34. Theforward osmosis membrane of claim 32 wherein the forward osmosis flux isgreater than approximately 60 LMH and urea rejection is greater thanapproximately 60%.
 35. The forward osmosis membrane of claim 32 whichutilizes a forward osmosis separation method that is not the solutiondiffusion mechanism.
 36. The forward osmosis membrane of claim 32 usefulfor filtering a fluid selected from the group consisting of wastewater,wastewater comprising surfactants, wastewater comprising an emulsion,bilge water, grey water, laundry water, and emulsions.